THE GONADS OF THE FOWL 85 



described in the following pages, the granule-laden cells are but 

 the young stages of the eosinophile leucocytes. Although a 

 description of the processes involved in the formation of the latter 

 is given, the present contribution does not aim to throw any light 

 on the much-discussed question of the origin of blood. It was 

 found necessary to study their relations to blood, in order to prove 

 that the granule-laden cells cannot be regarded as elements hav- 

 ing an endocrine function. At the same time, an attempt has 

 been made to determine to what extent the blood-forming ele- 

 ments contribute to the make-up of the complex tissue lying be- 

 tween the seminal tubules and between the ovarian follicles. 

 Once this is done, it will be easier to reach an understanding as 

 to the kind of cells which by their secretion produce the remark- 

 able condition in the plumage of hen-feathered cocks, explaining 

 at the same time the results brought about by castration in the 

 latter and in the normal female. 



MATERIAL AND TECHNIQUE 



The material used in this work consisted of the testes and ovaries 

 of twenty-six birds belonging to the races Sebright bantams 

 and Rhode Island Reds; the gonads of the latter W'Cre preserved 

 for me by Doctor Goodale. Thirteen of the specimens studied 

 were gonads from embryos ; the other thirteen belonged to young 

 chicks, four, five, and eight days old. In addition to this mate- 

 rial, sections of the gonads of several adult birds were also studied. 

 The source of this material and the methods used in their preser- 

 vation will be given in subsequent papers. 



The testes of embryos 10, 17, 18, 20, and 21 days old, attached 

 to the Wolffian bodies were preserved in Bouin's fluid w^armed to 

 37°C. The same treatment was used for the ovaries. The 

 gonads of the young chicks w^ere also preserved in Bouin's fluid 

 and a few in Zenker's mixture. 



Sections 7/x thick were stained chiefly with Delafield's hema- 

 toxylin and eosin and with iron hematoxylin, light green and 

 orange G as counterstains. I found unnecessary the use of Mann 

 and Mallory's stains. The sam.e results may be obtained by the 



