`

`PUBLIC HEALTH REPORTS
`
`
`
`
`N0. 23
`JUNE 8, 1928
`VOL. 43
`
`A STUDY OF THE BLACKTONGUE-PREVENTIVE ACTION
`OF 16 FOODSTUFFS, WITH SPECIAL REFERENCE TO THE
`IDENTITY 0F BLACKTONGUE OF DOGS AND PELLAGRA
`OF MAN
`
`and R. D. LILLIE
`By Joanna Gocnnnnoea and G. A. “-“nnncsa, b‘ur cons,
`and L. M. ROGERS, Passed Assistant Surgeons,
`cited States Pacific Health
`Service
`
`
`CONTENTS
`
`Introduction ................................
`Methods and 'L'n'teric .......................
`Maize (and cornstarch)_,
`_.
`Wheat...._._..-._-_
`
`Wheat germ__....-.
`_
`
`
`Cow aea. ._-. __
`..
`H.
`.
`_ _ _ .
`_
`Cottonseed oil ...............................
`
`
`
`Page
`Pu so
`142-1
`1385
`Beef.........................................
`14%
`138?
`Pork liver ..........................
`....
`
`143D
`1339
`Canned salmon.....................
`
`"H.212 1-131
`1392 Eggyolk._-..........______._...
`1394
`Tomatoes _______________________
`1434
`
`-
`1397 ' Carrots _________________________
`1435
`Rutahagas______.____c__._..._________
`____
`1400
`1443
`Relation of blacktonguc to peflagra.
`____
`1402
`1446
`
`1-105
`Summary and conclusions .....
`.
`344T
`1423
`References_____________________
`_ _ _ _
`1448
`1422
`Tables _________________________
`..__
`1449
`
`
`Some of the results of our study of the problem of an experimental
`animal for pellagra were briefly summarized in a communication
`published two years ago (1), and have been presented in detail in
`two recent publications.
`In the first of
`these Goldbergcr and
`Wheeler (2) reported the production in the dog, by feeding pellagra-
`producing diets, of a pathological condition considered by them to be
`identical with the spontaneously occurring canine disease known to
`American veterinarians as blacktongue.l The clinical resemblance of
`this canine disease to pcllagra in man was discussed and was consid-
`ered so striking as to be, in itself, practically conclusive of the identity
`of these- two conditions.
`In harmony with and supporting this View
`was also the suggestion of a common etiology indicated by the success-
`ful production of the canine disease by feeding with pellagra-producing
`diets.
`In the second communication, Goldbcrger, Wheeler, Lillie,
`and Rogers (3) reported a series of feeding experiments with yeast
`from the results of which they concluded that experimental black-
`tongue is due to a deficiency in diet that is capable of being corrected
`by something present in abundance in yeast. This demonstration of
`the presence of the blacktonguc preventive in yeast, a substance in
`which the pcllagra preventive (factor P-P) was also known to be
`present in abundance (4), was considered to increase somewhat the
`probability that blacktongue and pcllagra are fundamentally identical
`
`l Synonyms: Stuttgart deg epizootic; typhus our Hundc (dog typhoid); typhus of dogs: gastroenteritis
`hemorrhagica: southern canine plague. sore mouth of dogs.
`
`ioasso°—23——1
`
`{1335)
`
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`
`

`

`June 3,1923
`
`1386
`
`conditions.
`
`In this connection it is of interest to note that Danton
`
`(5)., in a study of the tissue changes in experimental blaclrtongue, has
`found that the lesions of the skin, mouth, pharynx, esophagus, and
`colon in the canine disease are very similar to those in pellagra, and
`that histologically the lesions in experimental blacktongue duplicate
`those in pellagra.
`In the body of this report reference will be made to differences
`between certain of the results of Our study and those of an apparently
`similar study by Undcrhill and Mendel (6). The divergence in our
`results is of interest, since we have heretofore considered it highly
`probable that the pathological condition experimentally induced in
`the dog by Chittenden and Underhill and studied by Underhill and
`Mendel was identical with the experimental condition studied and
`identified by us as blacktongue (2). The extensive report of their
`work (7) which has just. come to our attention presents some clinical
`details which not only seem in themselves significant of a difference
`in the two pathological conditions, but also sug est that We had here-
`tofore, perhaps, underestimated the significance of certain other clin-
`ical differences. Thus we find in this report that a “troublesome
`skin rash ” appeals to have been common in the condition with which
`Underhill and Mendel have worked. We have encountered none
`
`sueh in our dogs. On the other hand, while we have observed a
`pellagra-likc dermatitis of the scrotum in some 40 to 50 per cent of
`attacks in our male dogs, there is no mention of the occurrence of
`such an eruption in the condition studied by Underhill and Mendel.
`Again, in the condition studied by us—narnely, blacktongue—there
`is a definitely marked febrile stage which does not seem to occur in
`the Chi‘ttenden-Underhill syndrome studied by Underhill and Men-
`del; for they nowhere make mention of it, not even in their full report.
`These clinical differences seem to us of such importance that, in spite
`of the striking clinical similarity in certain other respects, doubt now
`arises as to the identity of the Chittenden—Underhill “pellagra-like”
`syndrome. Until this doubt is definitely resolved one way or another,
`it would seem premature to discuss, and we therefore do not attempt
`to discuss, the differences between the results reported by Underhill
`and Mendel and those recorded by ourselves in the present and in a
`preceding communication (3).
`In the present communication we present some further results of
`our study of experimental blacktonguc. These results deal with the
`blacktonguc preventive potency of certain select-ed foodstuffs, 16 in
`number, with special reference to the relation of experimental black-
`tongue of dogs to pellagra of man.
`
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`
`

`

`.1387
`
`June a. 1923
`
`METHODS AND CRITERIA
`
`The general methods of caring for and feeding our experimental
`animals have already been described (2) (3).
`1We may recall, how-
`ever, that the experimental diets were, as a rule, freshly prepared each
`day. The daily allowance of food Was, in general, intended to be no
`more than enough for the maintenance of normal body weight. An
`exception was made in the case of young growing animals, to which
`more than this allowance was offered.
`It may be recalled, too, that
`it has been our practice to use our dogs repeatedly with or without
`intermediate periods of stock feeding as might he demanded by the
`purpose of the experiment.
`In stock feeding, a definite food mixture
`has been used, principally our diet No. 156, the composition. and
`evidence of the adequacy of which have been given in a preceding
`communication (2).
`In testing for the blacktongue preventive we have employed both
`the curative and the preventive procedure, singly or in combination.
`Since, as We have in a preceding communication (2), already indicated
`the clinical course of experimental blacktongue, especially in the inva-
`sional stage, may normally be of an intermittent or relapsing char-
`acter, we attach no significance to a seemingly favorable therapeutic
`result in cases in which the treatment is begun early unless confirmed
`by the results of a preventive test. On the other hand, consistently
`unfavorable results of treatment under such favoring circumstances
`have been considered trust-worthy indications of a poverty in or lack
`of the blacktonguc preventive, provided that the test dose has been a
`liberal one. Our experience with experimental blacktongue has led
`us to consider the rise in temperature which occurs in the advanced
`stage of the disease as a mark of gravity (2). Only very enccptionally
`does the attack normally remit after this temperature rise has taken
`place. W’e have, therefore, been disposed to consider clinical recovery
`frorn the attack {that is, disappearance of all manifestations of the
`disease with recovery of appetite) following treatment begun at this
`advanced grave stage as significant, but have, nevertheless, always
`required confirmation by the preventive test before drawing final
`conclusions with respect
`to the presence of the preventive in the
`substance thus found to be active.
`Isolated cases of the apparent
`failure of treatment under these unfavorable circumstances have been
`
`considered as Without significance.
`In testing the individual foodstuffs, one, or exceptionally both, of
`two types of test diet have been employed.
`In the first the com-
`ponents other than the foodstuff under investigation are believed to
`have centriblltcd none or but an insignificant amount of the black-
`tongue preventive; in the second, some, at least, of the basic com-
`ponents may have contributed or probably did contribute a sub—
`stantial quota of
`the preventive. This difference in character of
`
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`
`

`

`June 8, 1923
`
`1388
`
`basic diet. should be kept in mind in evaluating and comparing the
`indications of preventive potency, since the results yielded by the
`former may probably be considered as due virtually entirely to the
`action of the foodstuff tested, whereas those of the letter must be
`considered. as a summation effect due to the combined action of the
`basic components and of the test- foodstuff.
`So far as our data permit, an appraisal has been made of the
`blaclrtongue preventive potency of each foodstuff.
`In view of the
`lack of a better practicable standard for such purpose, our appraisal
`is simply a judgment, in broad terms, of the preventive adequacy of
`such a quantity as, according to Conventional practice, represents
`the daily allowance for an average adult human male.
`The experimental disease in the dog and its diagnosis have been
`described in a preceding report
`(2); we need recall only that the
`earliest distinctive huecal signs are a vivid red injection of the
`mucosa of the floor of the mouth or a peculiar reddening of the
`mucosa of
`the upper lip in the form of bilaterally symmetrical
`patches, or of both. We have considered the first appearance of
`these mouth lesions as marking the beginning of the attack of black-
`tongue. We have conformed to this rule in all cases, even in those
`relatively few instances in which the pellagralikc dermatitis of the
`scrotum appeared in advance of the mouth lesions. Thus marked,
`the beginning of the. experimental disease, when this is induced by
`feeding our basic diet No. 123 (or certain of its modifications, namely
`diets No. 209, No. 195, and No. 268), is only very exceptionally de-
`layed beyond about 60 days after the beginning of the feeding (2).
`We have therefore been inclined to consider a very notable pro-
`longation of this period, pru‘ticularly when manifested in more than
`one of a group of test animals, as significant of the presence in the
`test diet of the blaclttongue preventive in an amount that is some-
`what larger than that presumably contained in our standard basic
`diet.l
`Since other factors, not yet understood, such, for instance, as
`self-imposed starvation or semistarvation and other possibly co—
`existing deficiencies or maladjustments of dietary essentials, may
`and probably do influence the duration of what for convenience. may
`be designated as the deprivation period, we have tried to exercise
`due caution in the interpretation of such indications.
`
`1 Our basic experimental diets of the type exemplified by our diet No. 123 tTabIe 1) contain, we iudge.
`asmall amount of the blacktongue preventive derived from its natural-food component a, principally corn
`meal and cowpem. We have the impression that the “synthetic" type oidlet otpuriuerl foodstuffs which,
`presumably, is entirely freeof the blacktongun preventive, is not as satisfactory an experimental diet. prior
`cipelly because 01 a more unfavorable effect on appetite leading to earlier and more marked sell-imposed
`starvation or semistarvation.
`
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`
`

`

`1389
`
`MAIZE
`
`June 3. 1923
`
`The idea that the maize in the diet is in some way concerned in
`the causation of pellagra has, as is Well known, been entertained by
`students of that disease almost from the time of its first recognition.
`It seems to have arisen in part, at least, because maize constituted a
`veryr large part of the diet of the populations among whom, in the
`Old World, the disease was endemic.
`In the United States, maize
`also is a conspicuous element in the diet of the population in the
`area where the disease is most prevalent, Both in the Old and in
`the New World, therefore, maize is more or less prominently asso-
`ciated with the occurrence of pellagra. While the extreme position
`of certain zeists that there is no pellagra without maize is new no
`longer tenable,
`the association is no doubt very common. One is
`justified in concluding, therefore, that maize is very poor in or lacks
`the pellagra preventive.
`In constructing our experimental diets, based as they are on diets
`found in association with the occurrence of pellagra, maize was from
`the first included as a conspicuous element. The basic diet most
`frequently used by us for the experimental production of blaektongue
`(diet No. 123, shown in Table 1) contains 400 grams of maize meal
`per 2,400 calorie ration. This is a large amount of cereal, consti-
`tuting as it does two—thirds of the weight of the dry ingredients of
`the diet. Notwithstanding this, however, as has in a preceding com-
`munication (3) already been set forth, dogs fed this diet (including
`certain of its modifications) have developed blacktongue within a
`period which only exceptionally exceeded a duration of about 60
`days. This would indicate that, as measured by the requirements
`of the dog, maize contains little if any of the blacktongue preventive.
`Incident-ally, it may be noted that cornstarch would also appear to
`be very poor or lacking in the blacktongue preventive since, as pre-
`vioasly reported (3), two dogs fed a diet (No. 281) containing 366
`grams of cornstarch per 2,400-calorie portion promptly developed the
`disease.
`
`The maize meal used in our basic diet No. 123 (including its modi-
`fications) does not, however, represent quite the whole kernel, since
`a small part of the bran is removed by sifting as if for human con-
`sumption.
`It seemed desirable, therefore, to test a meal from which
`nothing had been taken away. But as it did not seem to us probable
`that the difference in the meal represented by the small amount of
`bran removed in sifting would of itself appreciably influence the result
`of feeding, and as we wished, if possible, to determine whether the
`maize kernel contains an appreciable amount of the blacktongue pre-
`ventive, it was determined to work with a diet containing as large an
`amount of whole meal as possible and yet one that so far as could then
`be judged was adequate for maintenance in all other respects. With
`these considerations in mind we carried out Experiment 1.
`
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`
`

`

`June 8,1928
`
`1390
`
`EXPERIMENT 1
`
`This was a test of the black tongue preventive ac t-ion of whole white
`maize meal which was incorporated in test diets No. 149 and No.
`14911.
`(Table 2.) These diets, which are identical except that the
`butterfat of one is quantitatively replaced by cod-liver oil in the other,
`are a slight modification of a maize diet studied by McCollum, Sim—
`monds, and Pitz (8), and by them considered complete for normal
`growth of the rat to normal adult size, and for that reason selected
`by us for this study. Each contains 450 grams of whole—maize meal
`in a ration of slightlyr less than 2,400 calories. Suitable portions of
`one or the other of these diets were offered daily to each of seven test
`animals, dogs 29, 40, 52, 54, 57, 65, and 73. One of these dogs served
`during two separate periods, so that eight tests in all are to be con~
`sidered. The significant details relating to each of the test animals
`are presented in the following:
`
`Dog 99.-—Male. Acquired May 9, 1923. between which date and January 11,
`1924, served in a number of experiments and suffered four attacks of blacktongue,
`the latest of which began January 7, 1924. On a miscellaneous stock diet from
`January ll to February 5, 1924-.
`February 5, 1924: In good condition; weighs 11.1 kilograms; begins test diet
`No. 149.
`{Table 2.)
`On February 17, 1924, at the and of a period of 12 days, presented the first signs
`of an attack of blacktongue, an injection of the floor of the mouth. Further
`history not relevant.
`Dog 40.—Male. Whelped in the laboratory June 26, 1923, and reared on a
`stock diet. Up to February 20, 1924, served in a number of experiments and
`suffered two attacks of blacktonguc, the later one of which began February 19,
`1924. On a stock diet for reconditioning. from February 20 to March 11, 1924.
`March 11. 1924: In good condition; weighs 9.2 kilograms; begins diet No. 149.
`On April 23, 1924, at the end of a period of 43 days, presented the first signs of
`an attack of blacktongue, an injection of the floor of the mouth. Weight was
`11 kilograms. Further history not relevant.
`Deg 52.—Bitch. Acquired September 25, 1923. Up to February 20, 1924,
`served in a number of experiments and suffered two attacks of blacktonguc, the
`later one of which began February 18, 1924. On a stock diet for reconditioning
`from February 20 to March 11, 1924.
`March 11, 1924: In good cendition; weighs 9.7 kilograms; begins test diet No. 149.
`On July 31, 1924, at the end of a period of 14.2 days, presented the first signs of an
`attack of black-tongue, an injection of the floor of the mouth. Weighs 10
`kilograms. Further history not relevant.
`Dog 54.-—Biteh. Acquired September 25, 1923. Up to January 11, 1924,
`served in a number of experiments and sulfered an attack of blacktonguc which
`began November 28, 1923. On reconditioning diet-s from January 11 to March
`25, 1924.
`March 25, 1924: In good condition; weighs 8.1 kilograms; begins test diet No.
`149A.
`(Table 2.)
`On June 5, 1924, at the end of a period of 72 days, presented the first signs of an
`attack of blacktonguc, an injection of the floor of the mouth and a slight
`reddening of the mucosa of the upper lip on each side. Weighs 8 kilograms.
`Further history not relevant.
`
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`

`

`1391
`
`June s, 1923
`
`Dog Else—Male. Acquired September 25, 1923. Up to January 15, 1924,
`served in a number of experiment-s and suffered two attacks of blacktongue, the
`latter of which began December 13, 1923. From January 15 to February 5, 1924,
`on a miscellaneous stock diet for reconditioning.
`February 5, 192-1: In good condition; weighs 9.7 kilograms; begins test diet
`No. 1-19.
`011 February 23, 1924, at the end of a period of 18 days. presented the first signs of
`blacktongnc, an inject-ion of the floor of the mouth, of the mucosa of the
`checks, and of
`the anterior faucial pillars. Weighs 10 kilograms. Begins
`reconditioning diet.
`February 25, 1924: Redness of mucosa of the floor and cheeks is less pronounced.
`February 26, 1924: Redness has practically completely faded. Weighs 9.9
`kilograms.
`March 25, 1924: In good condition; weighs 10.1 kilograms; begins test diet No.
`149A.
`
`On April 11, at the end of a period of 17 days, presented the beginning signs of an
`attack of blacktongue, an injection of the floor of the mouth. Further history
`not relevant.
`
`
`Bile-ll. Acquired January 28, 1924. Kept on a miscellaneous stock
`Dog 65.
`diet to February 5, 1924.
`February 5,1924: In good condition; weights 5.7 kilograms; begins test diet
`No. 149.
`
`April 22: Weighs 7.7 kilograms.
`011 April 27, 1924, at the end of a period of 77 days, presented the first signs of an
`attack of blacktongue, a reddening of the mucosa of the floor of the mouth.
`Further history not relevant.
`Dog ”id—Bitch. Acquired March 19, 1924. On stock diet up to April I, 1924.
`April 1, 1924: In good condition; Weighs 7.7 kilograms; begins test diet. No. 14911.
`Jul)r 8, 1924: Weighs 10.2 kilograms.
`011 July 12, 1924, or 102 days after beginning the test, this animal presented an
`injection of the mucosa of the floor of the mouth suggestive of a beginning
`attack of bla-cktonglle. Two days later this was no longer perceptible, nor was
`there any reappearance of signs of blacktougue during a further period of
`observation of 38 days which ended August 19, 1924, on which date this
`experiment was discontinued.
`
`Results and conclusions—“Six of the seven dogs developed black-
`tongue in from 12 to 14?. days after beginning the test. The seventh
`(dog 73) presented evanescent evidence very suggestive but not con.-
`elusive of blacktongue at
`the end of a period of 102 days. The
`observation of this animal was discontinued at the end of 140 days,
`so that the possibility is not excluded that a definite attack of black-
`tongue would have developed had the observation period been longer.
`One of the test animals (dog 57) served during two separate periods
`and developed an attack of blacktongue in each. Thus the six
`animals in which definite evidence of blacktongue developed experi-
`enced,
`in all, seven attacks.
`Six of these appeared at the end of
`periods of not over 7? days in duration, and the seventh (dog 52)
`at the end of a period of 142 days.
`The unusually long interval before the development of the attack
`in one and the occurrence of but evanescent indications of an attack
`
`in another of the experimental animals, even though the observa-
`
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`

`

`June a, 1923
`
`1392
`
`tion period in the latter was but 140 days, suggest, by contrast with
`our experience with basic diet No. 123 (including certain of its
`modifications (3)), that the test diets under consideration may have
`possessed slight preventive properties. The difference is not very
`notable and, such as it is, can not be attributed, altogether at least,
`to the character and increased quantity of the maize, since one of
`the test diets (No. 149), unlike our standard basic diet (No. 123),
`contained some butter, which, as will presently be seen, while a poor
`source is not entirely devoid of the preventive factor, a fact that was
`not
`fully appreciated when this experiment was planned. This
`experiment is therefore not conclusive. Notwithstanding this, how-
`ever, the evidence quite clearly indicates that, at best, this cereal is
`a very poor source of the blacktongue preventive.
`Recalling the indications of its poverty in or lack of the pellagra
`preventive it would appear that maize, if it contains any, is a poor
`source of the preventive for both blacktongue and pellagra.
`
`WHEAT
`
`The important place among the cereals held by wheat and a desire
`to compare it with maize led us to test its blacktongue preventive
`potency. The following experiment Was accordingly carried out.
`
`EXPERIMENT 2
`
`For the present purpose, wheat ground in this laboratory into a
`meal was, without sifting, incorporated in a diet, No. 128, the com-
`position of which is shown in Table 3. This, as may be seen by refer-
`ence to Table 1, is essentially diet No. 123, the maize meal of which
`has been quantitatively replaced by the ground wheat, of which there
`are, therefore, 400 grams in each 2,400-calorie portion. Some of this
`diet was daily offered to each of eight test animals—dogs 5, 9, 13, 14,
`29, 38, 44, and 47. The significant details relating to each are briefly
`as follows:
`
`Dog ELHBitch. Acquired November 8, 1921. Has served in a number of
`experiments and has suffered two attacks of blacktongue, the later one of which
`began August 28, 1923. On stock diet from September 8, 1923, to January 29,
`1924. Whelped a litter of seven pups November 25, 1923, six of which sur-
`vived and were weaned in good condition January 17, 1924.
`(Table 3.}
`January 29, 1924: In good condition; begins diet No. 128.
`On August 2, 1924, at the end of a period of 186 days, presented the first signs
`of blacktongue, a reddening of the mucosa of the cheeks. To this there was
`added on August 3 a reddening of the mucosa of the floor of the mouth and of
`that of the upper lip on the left side. Further history is not relevant.
`Dog 9.——Male. Acquired April 1, 1923. Has served in a number of experi-
`ments and has suffered four attacks of blacktongue of which the latest began
`February 12, 1924. On stock diet. from February 13, to March 11, 1924.
`March 11, 1924: In good condition; begins diet No. 128.
`
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`
`

`

`1393
`
`June 8,1928
`
`On July 31, 1924, at the end of a period of 142 days, presented the first signs of an
`attack of blacktongue, a rcddencd patch on the mucosa of the upper lip, in the
`region of the canines, on each side, and a slight reddening of the mucosa of the
`floor of the mouth. Further history is not relevant.
`Dog 13.—Male. Acquired April 7, 1923. Up to November 28. 1923, served
`in several experiments and suffered three attacks of blacktongue, of which the
`latest began November 24, 1923. On a reconditioning diet from November 28
`to December 11, 1923.
`December 11, 1923: In good condition; begins diet No. 128.
`On February 20, 1924, or at the end of a period of 71 days, presented an injection
`of the floor of the mouth which was slightly more pronounced the next day,
`February 21. This reddening then persisted without notable change for some
`4.8 hours, then rapidly faded so that the mouth was normal on February 25.
`On July 11, or at the end of an additional period of 142 days, presented renewed
`signs of biacktongue, an erythcmatous patch on the mucosa of the upper lip
`on each side in the region of the canines and a slight reddening of the floor of the
`mouth. Further history not relevant.
`Dog lair—Male. Acquired April 7, 1923. Up to November 28, 1923, served
`in several experiments and suffered four attacks of blacktonguc, of which the
`latest began October 31), 1923. On a. reconditioning diet from November 28 to
`December 11, 1923.
`December 11, 1923: In good condition; begins diet No. 128.
`On June 24, 1924, or at the end of a period of 196 days, presented the first signs
`of an attack of blacktongue, a slight reddening of the mucosa of the floor
`of the mouth. Further history not relevant.
`Dog 99.——Male. Acquired May 9, 1923. Up to November 2?, 1923, served
`in several experiments and suffered three attacks of hlacktongue, of which the
`latest began October 18, 1923. On a reconditioning diet from November 27
`to December 11, 1923.
`December 11, 1923: In good condition; begins diet No. 128.
`On January 7, 1924-, at the end of a period of 2? days, presented the first signs of
`an attack of blacktongue, a reddening of the mucosa. of the floor of the mouth.
`Dog 38.——Ma1e. Whelped in the laboratory June 29, 1923. Up to February
`20, 192.4, served in several experiments and suffered two attacks of lJlaekt-ongue,
`the second one of which began February 14, 1924. On a reconditioning diet from
`February 20 to March 11, 1924.
`March 11, 1924: In good condition; begins diet No. 128.
`On June 24, 1924, at the end of a period of 105 days, presented the first signs
`of an attack of blacktongue, a reddening of the floor of the mouth. Further
`history not relevant.
`Dog 44.-—~Male. Whelped in the laboratory June 26, 1923. Up to December
`27, 1923, served in one experiment and suffered an attack of blacktongue which
`began October 28, 1923. On a reconditioning diet from December 27, 1923,
`to January 29, 192-1.
`January 29, 193-1: In good condition; begins diet No. 128.
`On August- 13, 1924, at the end of a period of 197 days, presented the first signs
`of an attack of blacktongue, reddened patches on the mucosa of the upper
`lip on each side. Further history not relevant.
`
`Deg (ii—Male. Acquired August 18, 1923. Up to November 28, 1923, served
`in an experiment and suffered an attack of blacktongue, which began September
`28, 1923. On a reconditioning dict from November 27 to December 20, 1923.
`December 20, 1923: In good condition; begins diet No. 128.
`
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`
`

`

`June 8, 1928
`
`1394
`
`On January 7, 1924, at the end of a. period of 18 days, presented the first signs
`of an attack of blacktonguc, a reddening of the floor of the mouth. Further
`history not relevant.
`
`Results and conclusions—As is evident, all eight of the test anim als
`developed blacktongue.
`It is noteworthy, however, that in but two
`of the dogs did the attack have its onset at the end of periods shorter
`than 71 days.
`In five of the eight animals the first signs of the attack
`made their appearance at the end of periods varying between 105 and
`197 days—that is, after periods very definitely longer than is the
`rule in the case of dogs fad diet No. 123. This delay in the develop-
`ment of the disease would appear to indicate that diet No. 128 had
`exercised appreciable but incomplete blaclttonguo preventive action
`and, therefore, that whole wheat contains the blacktongue preventive,
`but in small amount. Compared with the result of the experiment-
`with whole maize, the outcome of the test. of whole wheat suggests
`that this is probably a slightly better source of the blacktongue
`preventive than is the maize.
`WHEAT GERM
`
`While the preceding experiment with whole wheat was under way,
`tests were made of the lilacktongue-preducing potency of a number
`of diets in which were included varying amounts of commercial
`wheat germ as a source of “vitamin B.” The results of one of these
`tests which happened to he with a diet that included an unusually
`large quantity of the wheat germ, suggested rather strongly that this
`germ might possess definite blacktongas-preventive act-ion. This
`led us to carry out the following experiment:
`
`EXPERIMENT 3
`
`This was a test of the blacktongue-preventive action of ether-
`extracted wheat germ. The wheat germ was a commercial product
`from which we had extracted the fat by percolation with other
`(U. S. P.) at air temperature.1
`It was incorporated in a diet, No.
`197,
`the composition of which is shown in Table 4. As may be
`seen, each 2,400 calorie port-ion contains 180 grams of the extracted
`germ.
`It may he noted, too, that it contains a considerable amount
`of cornstarch; notably less, however, as was noted in the preceding
`section in connection with maize, than has been found to be lacking
`in appreciable blacktongue-prcventive action. This diet
`is some-
`what similar to our basic dict. No. 123 (Table 1), from which it differs
`notably, however,
`in that the wheat germ and the starch of
`the
`former completely replace the corn meal and cowpeas of the latter.
`
`Suitable portions of the diet were daily offered to each of nine test
`1 Various batches of this cthethrsctcd wheat germ were found by Assistant Chemist C, G. Harrisburg,
`in the Division of Chemistry of [he Hygienic Laboratory, to contain from 0.02 to 0.34 per cent of “ether
`extract?
`
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`
`

`

`1395
`
`June 3. 1923
`
`animals, dogs 54, 61, 55, 79, 71, 78, 86, 87, and 88. The significant
`details relating to each are presented in the following:
`
`Dag. 54—Bitch. Acquired September 25, 1923. Up to June 17, 1924, served
`in several experiments and suffered two attacks of blacktongue of which the
`second began June 5, 1924. On stock diet for reconditioning from June 17 to
`July 23, 1924. On an experimental diet, which included some wheat germ, from
`July 23, 1924, to May 26, 1925.
`(Table 3.)
`May 26, 1925: In good condition; begins wheat-germ diet No. 197.
`On September 19, 1925, at the end of 136 days, this animal presented a slight but
`very suggestive reddening of the mucosa of the floor of the month, which, how-
`ever was no longer perceptible 24 hours later. No further evidence suggesting
`biac ktongue appeared during the remainder of the period of observation, which
`ended May 26, 1926.
`In good condition at the end of one year on the wheat-
`germ diet.
`Dog 61 .~—Male. Whelped in the laboratory November 4, 1923. Up to May
`27, 1924, served in one experiment and suffered one attack of blacktongue, which
`began May 21, 1924. On reconditioning diet from May 2? to July 23, 1924.
`From July 23,1924, to May 26, 1925, on an experimental diet, which included a
`considerable amount of Wheat germ.
`May 26, 1925: In good condition; begins wheat-germ diet No. 197.
`On January 5, 1926, or at the end of a