Coli Changes in tlie Testis due to X Rays. 
273 
Fig. 8. Xormal young spermatocyte of the second Order situated about 30 jx 
from the basement mcnibrane of a seminiferous tubule. The nucleus exhibits a nuclear 
membrane within which coarse masses of chromatin are arranged upon an iiregular 
linin network; no nucleolus or intranuclear body is seen within the nucleus. The cyto- 
plasm, which is relatively abundant and is finely granulär, does not show any archo- 
plasm, but contains a large cliromatoid body, partly fragmented. 
Fig. 9. Normal spermatocyte of the second Order, showing homotype division, 
situated about one tliird. of the distance from the basement membrane towards the 
lumen of a seminiferous tubule. The nuclear membrane lias disappeared. A well marked 
spindle figure is seen with a centrosome visible at the lower pole. At the equatorial 
plane of the spindle about eighteen pairs of cliromosomes are seen; these are mostlv 
imperfectly rounded in appearance, but present obvious irregularities of outline. Below 
and to the left a large darkly stained mass is seen, probably a chromatoid body. The 
cytoplasm, which is abundant, is clear and granulär in aspect, and is bounded by a 
sharp margin. 
Fig. 10. Normal young spermatid situated about 25 fx from the basement mem- 
brane of a seminiferous tubule. The nucleus presents a well defined nuclear membrane, 
within which are disposed upon a linin network masses of chromatin usually of small 
size, four, however, being larger than the rest, Above and to the right an archoplasmic 
vesicle is seen lying upon the nucleus and containing an intermediate body closely 
applied to the nuclear membrane. On the opposite aspect of the nucleus, embedded 
in the cytoplasm, is a chromatoid body near which is a centrosome. The cytoplasm 
is relatively abundant, stains faintly, and exhibits a reticular structure. 
Fig. 11. Normal spermatid in further stage of development, situated near the 
lumen of a seminiferous tubule. The nucleus while still retaining its nuclear membrane 
stains nearly uniformly. Below, lying outside the nucleus is seen a chromatoid body 
and close to it a small darkly staining centrosome ; outside the latter a collar (mancliette) 
is recognizable. The cytoplasm which lies below the nucleus, is abundant and contains 
many small fatty masses together with the remains of the archoplasm; it exhibits 
a coarsely reticular structure. 
Fig. 12. Normal spermatid in more advanced stage of development, one of a 
collection attached to a cell of Sertoli lying on the basement membrane. The nucleus 
lias been converted into a Spermatozoon head at the base of which are seen two centro- 
somes, from one of which, almost in contact with the nucleus, the filament arises. The 
latter is covered with very fine darkly staining granules formed by mitochondria, 
and is surrounded by coarsely reticular cytoplasm, containing many fatty masses. 
Fig. 13. Cell of Sertoli situated close to the basement membrane of a semini- 
ferous tubule. The nucleolus, which exhibits a well-defined nuclear membrane, con- 
tains a moderate amount of chromatin arranged irregularly upon a linin network, a 
large nucleolus being also visible. The surface of the nucleus exhibits several clefts 
which extend some distance into the nucleoplasm, one of these being longitudinal. 
The cytoplasm is abundant, but its boundaries are only partly evident. 
Fig. 14. Spermatocyte of the first Order in spireme stage, situated nearer to the 
basement membrane than to the lumen of a seminiferous tubule. At the lower end 
of the nucleus is an intranuclear body, which lies at the lower part of the enlarged 
intranuclear vacuole, below which is some moderately stained material, the nature of 
which is not clear. Above the nucleus is an archoplasmic mass. The cytoplasm is 
tairly abundant and is granulär. 
