THE THYMUS 335 



of bloodvessels and dilatation of the heart. Grafting additional 

 thymus glands into young dogs caused serious disturbances 

 to health (Hart and Nordmann). 



Klose, and Klose and Vogt, performed a series of extirpation 

 experiments upon dogs between ten days and four weeks old. 

 These authors divide the post-operative period into three 

 stages : (1) A latent period, lasting from two to four weeks ; 



(2) an adipose stage, which lasts two or three months ; and 



(3) a cachectic stage, or the stage of " cachexia thymopriva " 

 and "idiotia thymopriva." This period extends to three 

 to fourteen months. Death occurs with "coma thymicum," 

 which often lasts a long time. The skeleton remains hypo- 

 plastic and dwarf -like, and the bones become atrophic. 

 There is a deficiency of undissolved calcium. Bodily move- 

 ments are feeble, and there are disturbances in the nervous 

 system. 



Interference with the growth, especially of the skeleton, 

 is also described by several observers. 



Changes in the pituitary and in the spleen after thymec- 

 tomy have been recorded. Perrier states that in the pituitary 

 there is an increase of the chromophilic cells. In the spleen 

 there is an increase of the reticulum and a hypertrophy of the 

 lymphoid tissue. 



The thymus does not appear to have anything to do with 

 the formation of red blood-corpuscles, nor with the growth of 

 epithelial organs. 



Soli states that extirpation of the thymus in adult hens 

 causes them to lay eggs without shells. This is the only evidence 

 which has been put forward up to the present time that the 

 thymus has any function after the period of involution of the 

 organ. 



D. A Probable Relation between the Thymus and the 

 Reproductive Organs 



Calzolari in 1898 suggested a relationship between the 

 thymus and the reproductive organs, and performed a series 

 of experiments upon rabbits, with the object of putting the 

 matter to the test. He found that in castrated male rabbits 

 the volume and the absolute weight of the thymus were 

 greater than in normal animals. He concludes that the 



