328 Kojima 



It will be seen that thirty days after castration there is no appreciable 

 difference in weight as compared with the controls, but in the castrated 

 animals which were kept forty-nine and fifty-seven days respectively there 

 is a very appreciable increase. 



Effects of Thyroid and Parathyroid Feeding in Rat 



(figs. 5, 6, 7, 8). 



The addition of 1 grm. of dry ox-thyroid or 3-4 grm. of fresh sheep- 

 thyroid to the ordinary diet for a week or more has the eftect of producing 

 diminution in number of the oxj'phil cells of the pars anterior. Those that 

 remain are for the most part swollen. The nuclei are not much enlarged, 

 but their chromatin granules are coarser and stain more deeply with hema- 

 toxylin. The cytoplasm of the basiphil cells is much more vacuolated than 

 that of the oxyphils. Some of their nuclei hardly stain at all with ha?ma- 

 toxylin. The principal or chromaphobe cells are in far greater number than 

 the rest. 



The intraoflandular cleft shows a considerable amount of colloid sub- 

 stance (fig. 5), and in one of the specimens large cysts, filled with a material 

 of similar appearance, are present in the pars anterior. 



If the thyroid feeding is intermitted and then again resumed, or if 

 continued for as long as a month, there is a gradual increase in the number 

 of the oxyphil cells. There is also some appearance of swelling in the 

 cells of the pars intermedia. When thyroid is fed to thyroidectomised 

 and parathyroidectomised rats the changes caused by those operations 

 are still evident, but there is a greater amount of hyaline sub.stance in 

 the gland (figs. 6 and 7). 



After feeding first with thyroid for a week and afterwards with 0"1 grm. 

 of dry ox-parathyroid, the oxyphil cells again appear abundant. A few 

 of these are swollen ; in some of these swollen cells the nuclei are only 

 very indistinctly stained with hasmatoxylin. Basiphil and chromaphobe 

 cells are relatively fewer. 



The efiect of thyroid feeding upon the pituitary of castrated male 

 rats was also investigated. Some of tlie castrated animals were fed 

 witli addition of 3 grm. of fresh sheep's thyroid to the food, and others 

 with addition of an equal amount of lean flesh (mutton): these served 

 as controls. The experiments lasted twenty and twenty-nine days 

 respectively. 



In the animals fed with thyroid there are many large vesicles con- 

 taining hyaline substance in the pars anterior, the appearance nearly 

 resembling that observable after thyroidectomy (fiof. 8). There are also 

 a large number of swollen cells. Oxyphil cells are far fewer in number 

 than basiphil. Many large drops of hyaline substance are to be seen in 

 the pars posterior. 



Table II. shows the weights of the pituitaries of four thyroid-fed 

 castrated male rats as compared with three castrated controls. 



