of Edinburgh, Session 1885 — 86 . 
805 
lie also described multinuclear cysts) ; they originate from blood 
corpuscles, and perform nutritive or mechanical functions. 
Over this a vigorous controversy at once arose. Merkel (1874) 
identified Yon Ebner’s spermatoblasts with his Stutzzellen, but while 
maintaining the origin of the sperms from the round cells, allowed 
that they were secondarily received into side pocket-like cavities of 
the Stutzzellen. According to Merkel, this secondary stage had 
thus been mistaken by Yon Ebner for the primary. 
The next important contribution was that of Sertoli, who 
described the fixed, ramified, epithelial cells as before, and identi- 
fying them with Merkel’s Stutzzellen and the lower part of Yon 
Ebner’s spermatoblasts, still maintained that they took no part in 
the actual spermatogenesis. This he ascribed wholly to the mobile 
round cells which arise between the fixed cells, and which he dis- 
tinguished in their youngest state as “ germinative,” and later as 
the larger “seminal” cells from the division of which the small 
numerous nematoblasts or undifferentiated spermatozoa result. 
Merkel was supported by Yon Brunn, and by Bloch who followed 
the development of the “round cells.” Neumann, on the other 
hand, denied the existence of Merkel’s framework altogether, and 
described free nucleus formation wfithin the spindle-shaped, first 
blunt, then fringed, spermatoblasts, which, differing from Yon 
Ebner, he regarded as modified from the ordinary epithelium of the 
tubule. He also described the origin of spermatozoids from free 
cells, which he explained as separated lappets of spermatoblasts. 
Krause (1876) also essentially supported Yon Ebner, but described 
the spermatoblasts as ciliated cells with ramified and even anasto- 
mosing processes, so doing away with a connective system altogether. 
Yon Ebner was further corroborated by Mihalkowics, Bivolta, and 
others, and his account of the processes has been perhaps most 
generally adopted (cf Landois, Frey, &c.). Blumberg (1873) 
attempted to reconcile the disputants by ascribing spermatogenetic 
functions to both spermatoblasts and round cells. 
Semper’s well-known researches on the urinogenital system of 
Elasmobranchs included an important contribution on spermato- 
genesis. He described an invagination of the germinal epithelium 
or of the primitive ova into the subjacent stroma, where they form 
a primitive follicle, which again comes into relation with the 
