368 
HERBERT H. BROWN. 
EXPLANATION OF PLATES XXII & XXIII, 
Illustrating Mr. Herbert H. Brown’s Paper “ On Spermato- 
genesis in the Rat.” 
PLATE XXII 
Represents sections of tubules from tlie testis of the Rat, stained with 
haematoxylin. 
Most of the figures in both Plates are drawn under a magnifying power of 
750 diameters, but Figs. 3, 8, 9, 10, 14, and 15 on a slightly smaller scale. 
Figs. 1 — 10 show consecutive stages in the production of spermatozoa. 
a. Spore-cell. o'. Ditto, dividing by fission, a". Cells dividing by karyoki- 
nesis to produce the young growing cells, b. Young growing cell in resting 
condition, b' . Ditto, in kinetic condition. b n . Growing cell at a later stage 
(in the second row), c. Young spermatozoa with spherical nuclei, c 1 . Young 
spermatozoa undergoing development, d. Adult spermatozoa, e. Supporting 
cells, x. Seminal granules. 
Fig. 11. — Nuclei of supporting cells, showing the large fatty -albuminoid 
globules (stage corresponding to Fig. 2). 
PLATE XXIII. 
Figs. 12 — 14. — Sections prepared with chloride of gold (lettered as 
Figs. 1—10). 
Fig. 12. Corresponds to Fig. 1. 
Fig. 13. Ditto to Fig. 5. 
Fig. 14. Ditto to Fig. 9. 
Fig. 15. — Section stained with osmic acid. Stage corresponding to Figs. 
14 and 9. 
Figs. 16 — 20. — Groups of developing spermatozoa from osmic acid prepara- 
tions, mounted in glycerine. 
Fig. 16. A group of young spermatozoa with oval nuclei. 
Fig. 17. Group of young spermatozoa at stage of Fig. 6. 
Fig. IS. Young spermatozoa slightly more developed, showing elongation 
of the protoplasm. 
Sci.,’ January, 1SS5, p. 107). In this paper the theory as to the separation of 
the female element from the spermatozoon and the male element from the 
ovum is also brought forward. 
