Cell Changes in the Testis due to X Rays. 
267 
4. Vacuoles possessing a cyst wall, embedded in the nucleus, but 
smaller than the preceding which they otherwise resemble. These do 
not occur singly, but are found in multivacuolate cells and cell masses 
and are associated with larger vacuoles, some of which can be recognized 
to be of type 3. They appear after the 3rd day. 
5. Vacuoles, which possess no clearly defined cyst wall, and cannot 
be recognized to be obviously surrounded, at any rate, throughout the 
whole of their extent by the nucleus (cp. smaller vacuoles in Fig. 25). 
They are arranged in groups, embedded in the same mass of cytoplasm, 
and vary from 3 u to 6 u in diameter. They occur in altered spermato- 
cytes of the first order and in spermatids, but are most abundant in 
multivacuolated cell masses. They have been observed chiefly on the 
4th to the 7th days. It is not certain that the smallest of these are sur- 
rounded by nuclear remains, but it is probable that they arise in Con- 
nection with the miniature nuclei njet with in some of the multinucleate 
cells. 
6. Vacuoles in the cytoplasm, not provided with a well defined 
cyst wall. They appear to be fluid collections and have been met with 
in the cells of Sertoli on the 3rd to the 7th days. 
Multivacuolate cell masses may be arranged in three groups, according 
as : 1. the vacuoles are completely surrounded by the nucleus or nuclear 
remains; 2. are incoinpletely surrounded by nuclear material; or 3. the 
relationship of the vacuole to nuclear material is uncertain. Multivacuo- 
late cell masses of the first dass appear to be derived from spermatocytes 
of the first order as the result of irregulär mitosis. The vacuoles do not 
possess a definite membranous cyst wall; sometimes they contain an 
intranuclear body, in other cases they are empty. Multivacuolated cell 
masses of the second dass are made up of numerous vacuolated spermatids 
which have presumably either become fused together or never had a 
separate existence, owing to the cytoplasm failing to divide when the 
daughter nuclei (of the spermatocytes of the second order 1 ) have been 
formed. The vacuoles appear before the head of the Spermatozoon is 
formed ; they possess a cyst wall and are of approximatelv the same size 
*) When four of these vacuoles are present the parent nuclei (derived from sperma- 
tocytes of the first order) must also be assumed not to have formed separate cells, but 
to have remained embedded in a common cytoplasm. If eight nuclei are present the 
daughter nuclei of the spermatogonia must be assumed not to have formed separate 
cells. Another possible explanation of the origin of these cell masses is that they occur 
in Connection with irregulär mitoses in spermatocytes of the first order or amitoses 
in spermatocytes of the second order. 
18 
