IO J. E. WODSEDALEK. 



tained through the courtesy of Professor L. J. Cole. Immediately 

 after the testes were removed from the live animal, pieces were 

 placed in various kinds of fixing fluids, as Bouin's, Zenker's, 

 Tellyesnicky's, and corrosive-acetic. 



Sections from various parts of the testes were made from four 

 to twelve microns thick and while several methods of staining 

 were employed, material fixed in Bouin's fluid and stained with 

 Heidenhain's iron hematoxylin with acid fuchsin as a counter- 

 stain, proved to be the most satisfactory. Delafield's hematoxy- 

 lin with eosin counterstain was also used and gave favorable 

 results. While material fixed in some of the other fluids men- 

 tioned was fairly good, the first method proved to be so superior 

 that the sections used in this study were almost wholly those 

 prepared according to it. Other material, from a much older 

 animal, was studied in sufficient detail to corroborate the results 

 obtained through the study of the material secured from the 

 younger and more vigorous animal. 



I also owe many thanks to Professor B. M. Allen for his 

 generosity in placing at my disposal his embryological material 

 of pigs of both sexes. The material in question, which was that 

 used by Dr. Allen ('04) in his own researches on the embryology 

 and development of the ovary and testes in mammals, was fixed 

 in Flemming's fluid and stained with Heidenhain's iron hema- 

 toxylin mainly. By examining a large number of these slides, 

 I not only corroborated my previous count of the spermatogonial 

 number of chromosomes, but was also able to make fairly con- 

 clusive counts of the chromosomes in the somatic cells of the 

 male, and in the oogonia and somatic cells of the female. With- 

 out the use of his material this important phase of the problem 

 could not have been worked out at this time. 



GENERAL ARRANGEMENT OF THE GERMINAL CELLS. 

 The structure of the testes of the pig does not differ greatly 

 from that of other well-known mammals, except for the presence 

 of numerous masses of large well-defined interstitial cells which 

 are scattered among the seminiferous tubules and comprise 

 about one fourth of the entire volume of the testes (Fig. i). 

 A detailed description of these interesting cells, which contain 



