PATHOLOGY AND SEMIOLOGY 225 



H. Matti describes the condition after thymectomy in very young animals 

 as somewhat different. After the latent period of about four weeks, during 

 which the animals remain behind in growth, manifestations occur in the osse- 

 ous system that are very much like those of high-grade rachitis. There occur 

 a high-grade softening and bowing of the bones and a rosary formation; there 

 is found a deficient apposition of calcium in the bones, the bone marrow is 

 hyperemic and the metaplasia in the fat marrow is slowed. The epiphysial 

 junctures are several times broadened. The examination of the blood only 

 shows that the decrease in lymphocytes which normally occurs with increas- 

 ing age and the increase in neutrophilic elements is slowed. Matti found 

 a broadening of the suprarenal medulla and a slight enlargement of the 

 thyroid gland and of the pancreas. The gray substance of the spinal 

 cord shows, as Klose and Vogt have already stated, signs of an increased 

 breaking up. At the close the animals lose the ability to walk and there 

 ensues marked cachexia that leads to death. The muscles show high-grade 

 atrophy of inactivity, with transitions to degenerative atrophy. 



In thymectomy in somewhat older animals these manifestations occur 

 only temporarily, yet when the extirpation was associated with removal of the 

 spleen, the animals, according to Klose and Vogt, for the most part died. 

 This would signify that the spleen takes over at least a part of the function of 

 the thymus gland. Matti could not find this. 



It should be mentioned further that castration in young animals essentially 

 delays the involution of the thymus gland and that increased sexual activity 

 accelerates it (Calzolari, Henderson, N. Paton, and Goddall, and others). 

 With this agrees the fact that in eunuchs, Tandler and Grosz found the thymus 

 gland hyperplastic. 



Svehla's experiments on hyperthymization have in part lost their signifi- 

 cance, as it has been shown by Popper that the depressor action of thymus 

 extracts intravenously is not specific, but is dependent on clots in the blood 

 path. 



Pathology and Semiology. Our knowledge as to the significance of the 

 thymus gland in clinical medicine is extremely deficient. As far as symptoms 

 in the absence of the thyroid gland in human beings is concerned we know next 

 to nothing. 



In the autopsy of new born and very small children aplasia of the thymus 

 gland has sometimes been found. The first statement is that of Bischojf. 

 Clark described an eight-month-old child that remained well up to the sixth 

 month. Then there developed hydropic swellings. Autopsy showed left- 

 sided hydronephrosis and aplasia of the thyroid gland, v. Sury describes a 

 case of congenital total defect of the thymus gland in a three-month-old child 

 who died of pneumonia. Aplasia of the thymus gland seems very frequently 

 to be associated with other malformations, especially developmental de- 

 fects of the brain (Winslow, Borneville, Katz, and others). On the other 

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