38 SPERMATIC PARTICLES. 



highest and best optical power known. Investigations of a later date, and upon speci- 

 mens taken fresh from the animal, have shown that the normal spermatic particles have 

 tails, but perhaps of the most transient nature.* 



Unless one has the best of eyes, and a still bettor instrument, I should think tiiat 

 they would be unwise to attempt the study of those bodies with fishes ; their bodies, or 

 rather cephalic portions, are from one eight-thousandth to one twelve-thousandth 

 of an inch in diameter, and their tails, when present, of a diameter nine or ten times 

 more minute, being in fact the smallest organic objects coming under the eye ot the 

 microscopist, and the clear definition of which may be taken as a fine test for a most 

 superior instrument. 



2d. Reptilia. — The spermatic particles of this class have been more thoroughly and 

 satisfactorily studied than those of any other class. This is due to their larger size and 

 more permanent characteristics througliout their several orders. Although there are 

 marked differences, yet they seem to have a general form, consisting of an oblong, staff- 

 like body, to which is attached a long thin tail. Among some of the different genera 

 of the same order, they appear so nearly ahke, that, were one examining them together, 

 care would be necessary in order to know from which genus they were taken. 



My own observations have been mostly among the Batrachia, and the mode of de- 

 velopment here seen may be, I am well assured, considered as expressing that of all the 

 other orders of this class. 



If, at the approach of the season of heat, the testicles be examined, there will be 

 found, in the midst of the normal epithelial cells lining the tubes, others larger, and hav- 

 ing a more opaque and prominent nucleus. These are the sperm ovules or cells. After 

 they have increased to four or five times their original size, the granulated nucleus seg- 

 ments, by a slight sulcus, which gradually deepens until the whole is divided into two 

 spheres. Each of these divides, and this subdivision goes on until the parent vesicle, 

 which has all this time been increasing in size, is filled with si^iall nucleated vesicles. 

 This condition of things is replaced by the presence of the spermatic particles, some- 

 times scattered in a random way throughout the vesicle, but commonly in a fasciculus. 

 (Vid. Fig. 12-21.) 



Having thus watched the vitalizing processes immediately preceding their formation, 

 our inquiry is here, as it has been before, — Are they formed by the elongation of the 



* Czermak {Beitrdge zu der Lehre von den Spermatozoen, Wien, 1333) says positively that the spermatic 

 particles of fishes have tio tails. Dujardin, however, from his observations on the' Carp, believes that they 

 are tailed, but shows that they can only be seen as suck when fresh. (Vid. Annal. des Sci. Nal., N. S., 

 Tom. VII. pp. 291 - 297.) 



