interpreted the malady of the chicken as the analogue of beriberi in Oriental countries it has been found that the domestic fowl is subject to a

Transcription

1 POLYNEURITIS IN FOWLS: ITS PERIPHERAL NERVOUS LESIONS AS COMPARED WITH WALLERIAN DEGENERA- TION. By PAUL G. CULLEY, A.M., M.D. Experimental work done in the Department of Physiology, Cornell University, Ithaca, N.Y. (Received for publication 30th September 1926.) HISTORICAL REVIEW. IN connection with the elimination of beriberi from the population of Oriental countries it has been found that the domestic fowl is subject to a disease which has many features in common with beriberi. As early as 1897 EIJKMAN (1), medical officer to a prison in Java, noticed that the poultry which fed upon the garbage from the hospital showed signs of paralysis strikingly suggestive of those of his patients, and died with extensive degeneration of the peripheral nerves. This chance observation led him to conduct systematic experiments with pigeons and chickens. He fed some on rice in the whole grain, including the husk; others he fed on rice lacking the husk, but retaining the pericarp, or " silverskin," and the germ; and a third series was fed on rice which had been both milled and polished. EIJKMAN'S results showed positively that on a diet of polished rice there appears in fowls a condition of nervous degeneration which he called polyneuritis gallinarum. He interpreted the malady of the chicken as the analogue of beriberi in man, and the consensus of opinion since then supports his view. EIJKMAN first attributed the disease to the lack of a substance found in the pericarp, which neutralises the injurious influence of the starchrich diet, but in 1906 he changed his idea essentially to that maintained to-day. In the same year HOPKINS of England came to the conclusion that there is some factor in the diet, essential to the growth of animals, which could not be accounted for among the known nutrients. These and other investigations paved the way for FUNK'S (2) separation, in 1911, of what he called vitamine-an essential factor in the food, the lack of which causes polyneuritis or beriberi. When in 1898 the United States acquired supervision of the Philippine Islands, there was sent over a number of scientists to determine the needs of the people and to make an attempt to improve their physical welfare. Among the results of their work was a drastic reform VOL. XVII

2 66 Culley of the unwholesome condition of the prisons, whose inmates were poorly fed and treated. One of the improvements was the use of clean white rice in the prisoner's diet. The first year after this saw an alarming increase in the number of cases of beriberi, so that the small group of laboratory scientists was confronted with an epidemic of startling proportions. With suspicion fastened on the diet rich in rice, the humble fowl was called upon to undergo the rigours of experimental life. In other places mammals were also used in studies relating to polyneuritis. Using dogs, cats, rats, a goat, and an ape, SCHAUMANN found that in all of them the characteristic signs of the disease became evident. Only mice failed to develop polyneuritis. HOLST (3), GRIJNS (4), and many others have done extensive researches, confirming the conclusions of EIJKMAN. In a report by FRASER and STANTON (5) it is stated that " the nerves of fowls suffering from this disease show typicai Wallerian degeneration," arnd this statement has been verified by many investigators. VEDDER and CLARK (6) in 1912 reported a thorough study of the neuritis in avian beriberi, examining the vagus, sciatic nerve, and spinal cord. By the Marchi method they found changes indicative of degeneration in the fibres of the sciatic nerve of every one of fifty-six fowls, which had been fed thirty-five days or more on polished rice, regardless of whether symptoms of neuritis had or had not manifested themselves before death. " Advanced degeneration in the peripheral nerve fibres manifests itself by a change in both myelin sheath and in the axis cylinder. The myelin sheath breaks up into globules and droplets, which stain black in the Marchi solution-indicative of fatty degeneration. The axis cylinder breaks up into segments or disintegrates in all those fibres showing advanced degeneration in the medullary sheath. " A variable period of incubation of the disease has been remarked by all observers; and the onset of symptoms may also be postponed to an extremely late date by retaining in the diet an amount of rice polishings, or other food stuffs, which is insufficient to afford complete protection. Thus, some of the fowls in the experiments of VEDDER and CLARK developed neuritis after ninety days' feeding, and EIJKMAN records a case where neuritis appeared only after a year's feeding. It is probable that there is no absolute immunity against this avitaminosis. GIBSON and CoNcEPcioN (7), e.g., found that even unpolished rice affords only partial protection against beriberi, and all the fowls of their experiment, fed on palay, developed polyneuritis, one after four months. FINDLAY (8), in his exhaustive study of avian beriberi, found that his fowls developed symptoms in from 18 to 74 days, the average being 31P5 days. VEDDER and CLARK (6) observe that " fowls show alteration in the medullary sheath of the sciatic fibres after only seven days on polished rice diet.... The stainable material shows remarkable

3 Polyneuritis in Fowls 67 alterations and occurs in the form of irregular, branched, and anastomosing masses. " In fowls fed for a longer period, these masses show, in a certain percentage of the fibres, progressive changes which manifest themselves in the form of more definite skeins and segmentations and larger masses and globules of stainable material. In fibres showing marked degeneration by the Marchi method these occur as larger or smaller vesicular, oval globules and correspond to the black globules shown by the Marchi preparations. In regard to the manner of recovery from the lesions of polyneuritis, one does not find as much information as might be expected from the amount of work done in this field. VEDDER and CLARK (6), in their classical work, found that fowls show as much individual variation in recovery as they do in developing the affection. In examining the nerves of fowls carried toward recovery by feeding for sixty days, well after neuritic signs had disappeared, they found still some segmentation and globular arrangement of the myelin, and loss of axis cylinder. FINDLAY (8) agrees that " administration of vitamine B cures the symptoms of paralysis in a few hours in birds, but does not repair the degeneration in the myelin sheath. " DUTCHER'S (9) interesting observation should be mentioned: that he saw a pigeon, suffering from polyneuritis in an advanced stage, eat a cockroach. The following day the bird was active in its cage, and its temperature had risen from C. to C. "The effects of the insect were noticeable for fourteen days, at which time the pigeon again began to show the effects of rice feeding." PRESENT INVESTIGATION. It is obvious that regeneration of a nerve fibre within the few days, or even hours, necessary for recovery from all signs of paralysis, is contrary to the accepted facts of physiology. What, then, is the condition of the fibre which allows of so early restoration of its function after what is reported to be Wallerian degeneration? The present investigation was undertaken, at the suggestion of Dr SUTHERLAND SIMPSON, with the purpose of ascertaining whether the degeneration of nerve fibres seen in polyneuritis is identical with Wallerian degeneration. In 1850 WALLER reviewed the subject of nervous degeneration, and formulated the fundamental law of the physiology and pathology of the nervous system known by his name. That part of his law which concerns our work has been proven true by countless workers-viz. that on severing the connection of a medullated nerve fibre with the central nervous system, or with its cell proper, a profound change occurs, with breaking up of the myelin sheath and fragmentation of the axis cylinder. In order to establish a standard with which to compare the nerves

4 68 Culley of fowls suffering from polyneuritis, seven healthy white Leghorn hens were operated upon under ether anaesthesia; one sciatic nerve in each hen was severed, without suturing the cut ends, near the beginning of its course in the leg; and the hens were sacrificed at various intervals after the operation. By this means a series of nerves was obtained which show the phases of degeneration from one to nine days after severance. One normal sciatic nerve from each fowl provided a check upon the degenerative change. None of the surgical wounds showed septic complications. A second series of eighteen white Leghorn hens was placed upon a diet of polished rice, and at intervals the sciatic nerves were removed from one or a pair of hens. Duplicate specimens of all nerves removed were fixed in osmic acid (1 per cent. solution), and in ammoniated alcohol, for silver impregnation by the Cajal method. After eight weeks of feeding on polished rice four of the hens were returned to a balanced diet, and were sacrificed, two after four days, and two after eight days. From hen 10, which showed signs of advanced polyneuritic paralysis, a portion of sciatic nerve was removed surgically two days before its death. The picture of sixty hours' Wallerian degeneration superimposed upon forty-two days' polyneuritic degeneration is impressive. OBSERVATIONS. The sciatic nerves from the first group of hens provided us with a series of pictures showing the well-known W7allerian degeneration at stages of from thirty hours to nine days. The disintegration of the axis cylinder, as shown by the Cajal method of staining, followed closely after the disintegration of the myelin sheath. The sciatic nerves from the second series of fowls, fed on polished rice exclusively, show progressive disintegration of the myelin sheath, beginning with an irregular swelling noted after seven days. Alteration of the axis cylinder does not necessarily accompany this change. After hen 14, for example, had been on a diet of polished rice for eight weeks there was extensive fragmentation of the myelin, but it is impossible to distinguish the axons from those of a normal fowl. W e found, however, that there wvas a correspondence between the onset of symptoms of polyneuritis and the changes in the axis cvlinder. Definite alterations were first noticeable in the neuraxons from hen 5, and this hen was apparently in an early stage of polyneuritis when killed. Similarly, in hens 7, 8, and 9, the early signs of polyneuritis were not separate from the axonic alterations. In hen 10 there developed an extreme condition of polyneuritis, waith fatal termination, and the axis cylinders from this fowl show considerable fragmentation. On the other hand, during the incubation period of the disease, before any symptoms of paralvsis are manifested, there is no alteration

5 Polyneuritis in Fowls distinguishable in the axis cylinders, while the myelin shows a definite deviation from the normal, similar to early Wallerian degeneration. The nerve which underwent sixty hours' Wallerian degeneration, superimposed upon forty-two days' polyneuritic degeneration, has the microscopic appearance usually seen in fibres which have been severed not less than 120 hours (five days). COMMENT. We are inclined to doubt the validity of the conclusion of VEDDER and CLARK that "the symptoms of the disease are not chiefly referable to degeneration of the peripheral nerves, since the degeneration occurs before symptoms arise, and because advanced degeneration may be present, accompanied by no symptoms at all, and because degeneration of the nerves remains after recovery has occurred." In the light of the present study of the condition of the axis cylinder in various stages of polyneuritis, it seems correct to attribute the paralytic symptoms, at least partially, to the loss of conductivity by the nerve fibre. It is obvious that a disturbance of the integrity of the fibre at any single point in its course will result in the abolition, functionally, of the neuro-muscular connection-in other words, paralysis of the innervated muscle ensues. If, as is believed by some neurologists, the propagation of the nervous impulse is a phenomenon of polarisation, there is little difficulty in believing that the change in the axis cylinder seen in polyneuritis, especially the alteration in the periphery of the axon, is sufficient to disturb the power of movement, by destroying the conductivity of the nerve fibres. When a sufficient number, relatively, of the fibres are affected, paralysis of the limb will be manifested. In view of FINDLAY'S report of the disappearance of Nissl granules in cases of polyneuritis, one would wish to study the relation between that change and the degeneration of the neuraxon. The conviction should be recorded that the experiments in which polished rice alone is used as a diet are not satisfactory for a study of avitaminosis. There is so much more lacking than vitamine B, that the effect upon the animal is necessarily due to a summation of deficiencies. To attack the present problem, however, we were interested not so much in studying a deficiency of vitamine B as in producing the polyneuritic degeneration observed by the various workers consulted. SUMMARY. 1. The degeneration of peripheral nerve fibres in polyneuritis is not identical with Wallerian degeneration. 2. Symptoms of polyneuritis gallinarum were observed to correspond in time and rate of onset with changes in the neuraxon, being independent of the condition of the myelin sheath. 69

6 70 Polyneuritis in Fowls To the memory of Dr SUTHERLAND SIMPSON is due a word of appreciation. Not only did he suggest the present investigation, but through instruction in his "clinics of physiology," as we may term them-his never boresome lectures-it has been the privilege of the writer, along with many others, to be inspired to the desire to help chart the hitherto unknown regions of life. REFERENCES. (1) EIJKMAN, Archiv. pathol. Anat., Berlin, 1897, cxlviii (2) FUNK, Journ. Physiol., , xlv. 75. (3) HOLST, Soc. Trop. Med. and Hyg., 1911, v. 76. (4) G1RIJNS, Geneesk. Tidsch. Med. Ind., 1901, i. (5) FRASER and STANTON, Phil. Journ. Sci., 1910, v. B, 56. (6) VEDDER and CLARK, Phil. Journ. Sci., 1912, vii. B, 423. (7) GIBSON and CoNCEPCIoN, Phil. Journ. Sci., 1914, ix. B, 119. (8) FINDLAY, Journ. Pathol. and Bacteriol., 1921, xxiv (9) DUTCHER, Journ. Biol. Chem., 1918, xxxvi. 551; and 1919, xxxix. 63.