Sperm Formation in the Domestic Animals 

 with Consideration of the Sterility and 

 Fertility in Mules" 



WILLIAM M. GOLDSMITH, Indiana University. 



I. Introduction — Stimulated by the ap- 

 pearance of Wodsedalek's paper (January 

 1016 Biol. Bull.) on the spermatogenesis of 

 the horse, I conceived the idea of making a 

 similar study of the germ cells of the com- 

 mon mule, with a view of ascertaining the 

 cause of sterility in this valuable beast of 

 burden. The first great difficulty which con- 

 fronts the cytologist in undertaking such a 

 laborious problem, is in obtaining the desired 

 material. In the spring of 1915 this matter 

 was taken up with the president of the Ohio 

 Valley Veterinary Medical Association, Dr. 

 Walker France, who considered the problem 

 of sufficient importance to justify him in 

 rendering assistance. More than a week was 

 spent in "Fording" over the liills of Pike and 

 Gibson counties with the doctor in one of his 

 mad wholesale slaughters of the future 

 progeny of horse colts and the useless pas- 

 sion of as many mules. To the amusement 

 of the farmers, the testes were greedily 

 snatched from the doctor's knife, cut into 

 small bits and placed in Fleming, Bouin, al- 

 cohol, acetic and picroacetic fixations, which 

 are extensively used by the cytologist. 



At that time I was working on the plas- 

 mosome or achromatic nucleolus, of one of 

 the true bugs, and was not in position to 

 turn my personal attention to the newly col- 

 lected material, until the plasmosome paper 

 was in the hands of the publishers. In the 

 meantime, Mrs. Goldsmith, while working at 

 the Indiana University Biological Station, 

 prepared and studied a vast amount of this 

 material. After three months' work, it was 

 found that all animals, both horse and mule, 

 from which the material had been taken, were 

 too young, as none of them contained mature 

 cells. This material was then stored for fu- 

 ture use and arrangements made with Dr. 

 France and other veterinarians, to assist in 

 the collection of material from older animals. 

 However, in January 1916 all plans were 

 abandoned when a paper on "The cause of 

 Sterility in the Mule" by J. E. Wodsedalek, 

 of Idaho University, made its appearance in 

 the Biological Bulletin. Since our observa- 

 tions on the earlier germ cells of both the 

 horse and mule agreed with those of Wod- 

 sedalek, and further since the problem was 



Read before the Ohio Valley Veterinary Medical 

 Association, Terre Haute, Indiana, Feb. 13, 1917. 



given up in recognition of his valuable work, 

 the speaker wishes to present this paper only 

 as a brief treatise on some of the old and 

 new phases of this subject, and not as a 

 cytological contribution. It should be recog- 

 nized, however, that many months' time has 

 been spent on the problem and much first 

 hand knowledge obtained. 



In presenting a paper such as this, it seems 

 wise to sacrifice technical details for a gen- 

 eral and more comprehensive discussion. I 

 desire, then, to briefly discuss the general 

 methods of sperm formation and to refer 

 the cases of various domestic animals to this 

 general type. It is quite a long and com- 

 plicated process to follow the history of a 

 cell or group of cells from a non-differen- 

 tiated germ layer of a tiny embryo, to a 

 mature sperm of the adult, indeed, much more 

 taxing than to listen to even a non-technical 

 paper on the subject. 



II. Differentiation of the Germ Cells — 

 The maxim of Virchow 1855 "omnis cellula 

 e-cellula" (all cells come from cells), after 

 being tested from all angles for more than 

 three score years by the world's most pains- 

 taking investigators, has come to be uni- 

 versally accepted. Since, according to this 

 theory all the cells of the body must have 

 originated from a single cell, and further 

 since this single cell can be traced back to 

 the ovaries and testes of the parents, it is 

 obvious that there are two types of cells. 

 These are referred to as somatic and germ 

 cells. The former, which constitute the body 

 tissue, live through a life cycle and then die, 

 while the latter have an immortal life. Ac- 

 cording to this conception the individual is 

 composed of millions of sub-branches from 

 one single off-shoot of the germ cell. This 

 might be illustrated by a vine which sends up 

 annual shoots. The plants themselves die, 

 but underneath the surface the roots con- 

 tinue to send up new sprouts each year. The 

 branches of the vines, which spring up and 

 then die, correspond with the somatic cells 

 of each individual, while the underground 

 roots are homologous with the never dying 

 germ cells of the ovaries and testes. Thus 

 each individual germ cell constitutes only a 

 small link in the chain of life flowing from 

 the ovaries of Eve to the final destruction of 

 the human race. It is interesting to note that 

 from the standpoint of somatic cells, the 



