THE SEMINAL FLUID. 



945 



The spermatozoa of the frog may be frozen four times successively without 

 injury; they endure a heat of 43.75 C. and continue to live for seventy days 

 in the testicle transplanted to the abdominal cavity of another frog. 



On account of the large proportion of earthy salts they contain, spermatozoa can 

 be fused on a glass slide and nevertheless retain their form, like trie cells of some 

 plants rich in ash, for example the equisetaceag. Nitric, sulphuric, hydrochloric 

 and boiling acetic acid, and caustic alkalies do not destroy the form of the sper- 

 matozoa. Solutions of sodium chlorid and potassium nitrate, of from 10 to 

 15 per cent., transform the spermatozoa into amorphous clumps. The organic 

 substance resembles the semisolid albumin of epithelial cells. 



In addition to spermatozoa the seminal fluid contains seminal cells, a few 

 epithelial cells from the vasa deferentia (isolated examples of which are in a state 

 of colloid degeneration) , numbers of lecithin-granules and occasionally laminated 

 amyloid bodies, granular or scaly yellow pigment, especially in later life, leuko- 

 cytes and sperm-crystals. 



The development of the spermatozoon (Fig. _ 3 55) has been made clear only 

 in recent times after considerable research, especially by v. Ebner, whose results 

 were obtained simultaneously and independently by the author. From the nuclear 

 protoplasmic layer (Fig. 355, /, b and IV, h} lining the inner surface of the wall 

 of the seminal tubules (/, a and IV, n), which is composed of several layers of 

 interlacing elastic fibers (interspersed with flat cells), large columnar processes, 



a 



FIG. 355. Spermatogenesis (Semidiagrammatic) : /, Transverse section of a seminal tubule; a, its sheath; b, its 

 protoplasmic internal layer; c, spermatoblast; s, seminal cells. //, Immature sperm atoblast; /, its rounded 

 upper lobules; p, seminal cells. ///, Spermatoblast with released spermatozoon; /, spermatozoon; p, 

 seminal cell. IV, Spermatoblast with mature heads () and cilia (r); n, wall of the seminal tubule; h, pro- 

 toplasmic layer of the tubule; p, seminal cell. 



0.053 mm - l n g (I, c an d //, ///, IV), project into the lumen. These break up 

 at their free extremities into several oval lobules (//) like ears of corn and are 

 known as spermatoblasts or seminal ears. These formations were first dis- 

 covered by Sertoli, who considered and designated them "supporting cells." 

 They consist of soft, finely granular protoplasm and contain an oval nucleus 

 usually in their lower portion. In the course of development each lobule of the 

 spermatoblast is prolonged into a long cilium, like the grains of an ear of corn 

 (IV, r) , and in the depth of the lobule the head and the middle segment of the sperma- 

 tozoon (IV, k) are developed from a condensation of the protoplasm. In this 

 stage the spermatoblast resembles a very large, irregularly formed ciliated cylin- 

 drical cell. When development is complete the head and the middle segment 

 become separated from the mother-cell (///, t} , and the remainder of the spermato- 

 blast, with its resulting goblet-shaped depressions, resembles a threshed ear of 

 corn (///, /). Later it undergoes fatty degeneration. The spermatozoon itself 

 often exhibits for a long time an adherent mass of protoplasm at the junction of 

 the head and the middle segment, representing a part of the spermatoblast 

 (///, t). In accordance with its development, the spermatozoon may be regarded 

 as a detached, independently motile cilium of a huge ciliated epithelial cell. Be- 

 tween the spermatoblasts lie numerous, round, ameboid, unencapsulated cells, 

 60 



