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(The speaker then discussed briefly the occurrence and clinical aspects of beri-beri, xerophthalmia, scurvy, pellagra, war edema ; urinary calculi in relation to diet; tumor growth and diet.)

The student of nutrition and dietetics finds numerous questions raised by these considerations. He inquires about the distribution and stability of the vitamines; the relation of infection to deficiency diseases; the sequences of the symptoms and their true interrelationship; more familiar deficiencies in proteins and salts, which have not been touched upon here because they are somewhat better known. My main purpose will have been accomplished if I have succeeded in leading you to evaluate more seriously the possible rôle of newly ascertained factors in a variety of clinical manifestations.

DISCUSSION.

DR. TILESTON (New Haven): Mr. President and members of the Society: Professor Mendel's work shows us what can be done by a physiologist when he directs his attention to the problems of disease. Formerly he devoted himself, almost exclusively, to the study of the normal functions, usually in animals, while the physician investigated diseased conditions only, and there was little co-operation between the two. Now, a new era has set in and great results may be expected by the collaboration of the scientist and the physician. The history of pellagra is a good illustration of this. For a great many years pellagra was known to be extremely common in northern Italy where the peasants lived almost entirely on corn meal. Owing to the bacteriological viewpoint of those days the cause was sought for in bacteria, and spoiled corn was thought to be the cause of the disease. It was really not until the disease was investigated by Goldberger in this country that much light was thrown on the cause of pellagra. This investigation by Goldberger is probably one of the finest pieces of research that has been done in this country, and the most extensive investigation of diet that has ever been performed. For a number of years he studied the dietetic habits in the little mill town of Spartanburg, N. C., and some of the adjacent villages where pellagra was very common. He studied the diet of each individual person and investigated all of the surrounding conditions. The inhabitants got most of their food from the village store and he was able in that way to find out what each family had bought; every month an inventory of the store was made to check up the results so that after a number of years he knew exactly what the diet of all the inhabit

ants was. He found that the people who had a cow and could get fresh milk, and those that bought a sufficient quantity of fresh beef were practically immune from the disease. He was able, moreover, by altering the diet at institutions where pellagra was very common, to root out the disease. Thus he proved very conclusively that pellagra was a deficiency disease.

Two

The vitamines were first discovered in connection with beri-beri. English investigators, Ferguson and Stanton, experimented with diets in a jail. They put a group of prisoners on a diet of polished rice from which the covering was removed, and the rest were used as a control and fed on the brown rice. Among those who took the polished rice, beri-beri developed and it was cured by adding brown rice to the diet. The prisoners who took the brown rice exclusively did not have beri-beri. Later it was discovered that the brown rice contained a principle which could be extracted, and this principle when added to the diet of polished rice would prevent the appearance of beri-beri, or would cure it after it had begun. The war edema that Prof. Mendel alluded to is an exceedingly interesting condition, with marked edema, chiefly of the legs, without any signs of disease of the kidneys. It has been described in Germany also among inhabitants who have had a very restricted diet with regard to fats, and it is regarded there as a fat deficiency disease. Since one of the essential vitamines is in the fat it is very likely, though not yet proved, that the condition is due to lack of vitamine. In this connection a comparison with beri-beri is interesting, because there is a "wet" type of beri-beri characterized by similar edema, but so far as I recall no cases of war edema have shown a peripheral neuritis, which is a regular characteristic of beri-beri.

Occasionally we meet with cases of infantile edema which may very likely be due to deficiency of vitamines. Such cases show a marked edema of the whole body.

Scurvy is another very interesting deficiency disease. Anyone who has watched a child with scurvy improve and get well in the course of a few days under the administration of orange juice cannot but be struck by the resemblance to Dr. Mendel's rat who received no water-soluble vitamines.

I was very much interested in the occurrence of phosphatic calculi in Prof. Mendel's rats. So far as I know in the case of calculi in man no relation has been noted to the diet of the patient, but there is a very great difference in the frequency of this disease in different localities. In India it is very common, but in China it is rare. It is possible that dietary habits might exert some influence.

I would like to say a few words in regard to the war diet and what will be the result of it. I think in regard to adults, nothing serious is to be feared. The most that will happen is that you will have carbo

hydrate indigestion, and that is a purely functional disease and produces only discomfort. In the case of children deficiency disease is likely to arise owing to the high cost of milk and the substitution of margarin for butter. Nut margarin has no vitamine in it. Margarin made from beef does contain vitamines.

PROFESSOR MENDEL (New Haven): The question you have raised is a most timely one. The problem of canning and preservation by drying and the different conservation processes has raised the question of how stable these vitamines are. I think no one is entitled at the present time to give a final answer to this question. Butter fat can be steamed for a long period and eggs can be cooked without entire loss of their vitamine. We can boil milk, and in fact one of the sources of vitamine that we use from milk has been boiled and dried by heat to a considerable degree; and likewise brewers' yeast that we have used very efficiently. I am not prepared to say that this particular property of food is not at all alterable by heat. I think that ought to be emphasized because there is this widespread opinion that Pasteurized or boiled milk is deleterious.

As I read the literature of infantile scurvy ascribed to boiled milk and heated milk, I can draw no conclusion that is so utterly opposed to the use of milk that has been Pasteurized and boiled. I should want to survey the evidence on both sides of the subject.

We are finding at the present time in our laboratories that the use of boiled and cooked vegetables do not have the same antiscorbutic properties that those do which have not been boiled or are dried below forty-five degrees temperature.

Enlarged Thymus Gland in Childhood.

HOWARD W. BRAYTON, M.D., HARTFORD

By way of introduction, the following facts may be of value: The thymus gland is situated in the upper part of the anterior mediastinum in close apposition to the trachea, great vessels, phrenic and pneumogastric nerves, and the heart.

Its size, in relation to the entire body, is greatest at birth, but the absolute weight of the gland steadily increases up to about the twelfth year, after which it undergoes gradual atrophy.

Very little is known concerning the function of the thymus other than that it is instrumental in the formation of lymphocytes, is complementary to many glands of internal secretion, notably the thyroid, and when totally extirpated in animals, produces fatal nutritional disturbances.

The chief clinical interest in the gland centers around its pathological enlargement during the first few years of life, particularly in infancy. Again, very little is known as to what constitutes the etiology of this pathological overgrowth, although from the fact that it is often found enlarged in rickets, syphilis, and certain toxic infections has led to the theory that its hyperplasia is an attempt to compensate for the lymphoid exhaustion of these diseases.

The symptoms of enlarged thymus may be divided into two classes, general and local. Under the former come the results of faulty endocrine function such as flabbiness of the tissues, lack of resistance to acute infection, liability to frequent convulsions, eczema, and mental retardation. Some infants never show these generalized disturbances but exhibit only the local symptoms which are referable entirely to the mechanical effect of the enlarged gland. From the fact that the thymus is situated in the upper part of a closed and rigid chest cavity, any gradual or sudden enlargement must of necessity produce pressure on the underlying vital structures. While it is universally admitted that this pressure may cause laryngeal spasm, heart shock, pul

monary engorgement, etc., it has been denied that a structure as soft as the thymus could press upon the trachea to the extent of causing obstruction. This contention seems to be faulty, however, for in one of our cases tracheoscopy showed an inward bulging to the extent of half the lumen of the tube at a point two inches below the vocal cords.

These local symptoms of thymic pressure are almost entirely respiratory in character and vary from a slight cough, coming on at intervals of a few days or weeks, to a dyspnoea of the most profound type. The cough is often croupy and paroxysmal, worse during feeding, and is out of proportion to the clinical findings in the throat and chest. During these attacks of cough there are often a few rales at the bases of the lungs, but whether this moisture is a mild exciting cause of the cough or whether it is a congestion due to obstruction of the pulmonary veins is not always clear.

Accompanying the cough or independent of it there is usually present a certain amount of dyspnoea which is largely inspiratory in type and aggravated during feeding and in the course of acute illnesses. The respirations at these times are distinctly audible. If the dyspnoea is at all pronounced cyanosis is likewise present and may vary in degree from a transitory bluish tinge to the lips and nails to a constant extreme lividity. When the asphyxia reaches a certain point death ensues or generalized clonic convulsions come on which may terminate in either death or recovery. Not all cases of thymic death are due to obstructed respiration, however, for in a certain number of those occurring suddenly during anaesthesia and after fright there is very little dyspnoea. It is probable that in these instances pressure of the acutely congested gland causes reflex heart shock.

The diagnosis of enlarged thymus must be made both from the history and physical examination. If cough, stridor or cyanosis are present in the history it is suggestive, but when the history is negative, examination alone must suffice.

Inspection (Slide 1) often reveals a flabby, poorly muscled child with a bulging of the upper front of the chest. Some authors have described the gland as visible in the suprasternal

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