STUDIES ON THE CELLS OF CATTLE. 2Q3 



material was then reinvestigated and new sketches were made 

 of many of the cells, the location of which was recorded before. 

 The results obtained through the study of new slides prepared 

 by the technician, as well as those obtained through the second 

 study of my original material were then compared with the 

 original results. Several hundred different germinal and somatic 

 cells from both sexes were carefully checked up. Especial atten- 

 tion was paid to the number of the ordinary chromosomes and 

 to the sex-chromosomes. Only in a comparatively few cases was 

 there any discrepancy in the interpretation of the nature and 

 number of the ordinary chromosomes. Conditions pertaining 

 to the sex-chromosomes were corroborated in every instance. 

 I was further checked up on my chromosome counts by several 

 of my assistants and senior pre-medical students who had con- 

 siderable training in microscopic anatomy. In general, these 

 men who knew nothing of my own interpretations, corroborated 

 my counts in a surprisingly large number of instances. 



II. MATERIAL AND METHODS. 



All of the material used in this investigation with the excep- 

 tion of some ovaries was obtained through the courtesy of the 

 management of the Hagan and Gushing Packing Plant which 

 adjoins the University farm. Some excellent ovarian tissue was 

 given to me by my colleague Dr. A. R. Hahner, formerly professor 

 of veterinary science of the University of Idaho. The ovaries 

 were removed from two five-months-old heifers of the university 

 herd. Testes were obtained from seven mature bulls and one 

 male foetus of five months and from six smaller foetuses varying 

 from two to eight and one half inches in length. The ovaries 

 were obtained from four heifers and as many cows, and from 

 five small foetuses, varying from two and one half to seven inches 

 in length. In addition to this six small embryos were sectioned. 

 Many slides were also made of various somatic structures from 

 the small foetuses of both sexes. 



Several fixing fluids were tried on the testicular material, in- 

 cluding Hermann's, Gilson's, Flemming's, and Bouin's. Bouin's 

 fluid used straight or with slight modifications, at 38 C. was the 

 most universally successful fixing agent. When used at some- 



