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J. 0. Wakelin Barratt and G. Arnold 
described in the preceding sections affect cell division, cell development, 
and cell nutrition, no purely functional affection of any seminal cells, 
not indicated bv structural changes, being as yet known 1 ). Disturbance 
of cell division is exhibited by in-egular mitoses and by amitoses, distur- 
bance of cell development is exemplified by archoplasmic vacuole for- 
mation, and disturbance of cell nutrition is seen in intranuclear vacuole 
formation. Attention will here be confined to these three types of func- 
tional disturbance which involve the more striking structural changes 
already described. 
Irregulär mitoses (Fig. 19) are very instructive, since they afford 
an illustration of the effect of disturbance of a single cell structure, for 
in such cases the cause of the altered appearance of the cell appears to 
lie primarily in a disordered condition of the centrosomes, some of which 
divide while others remain undivided. The result is that some of the 
spindles have a common pole. The spindles themselves do not appear 
to be otherwise affected, the spindle fibres being well formed. On the 
other hand, the centrosomes do not appear to be the only structure acted 
upon by X rays in such cases, for the chromosomes are generally not 
properlv formed, and not unfrequently individual chromosomes or small 
groups of chromosomes, are found not to be attached to spindle fibres, 
but at some distance from the spindle. Cells exhibiting multipolar mitoses 
seem to undergo necrosis readilv. Whether any further development is 
possible before this occurs is uncertain; we have not been able to trace 
the passage of cells exhibiting multipolar mitoses into multinuclear 
cells, though this is not improbable. 
Amitosis becomes marked in cells of Sertoli after the application 
of X rays, and is occasionally seen in spermatocytes of the second order. 
In the former case (Fig. 12) it is uncertain whether this is to be regarded 
as merely an exaggeration of a normal function or whether the type of 
cell division has been changed, for in normal festes it does not seem pos- 
sible to observe division in cells of Sertoli, apparently partly in conse- 
quence of the relative rarity with which this process occurs in such cells. 
In spermatocytes of the second order, on the contrary, mitosis which is 
the ordinary mode of division is readily observed in healthy festes, but 
amitosis does not appear to occur. In this cell type, therefore, amitoses 
following on exposure to X rays must be regarded as an anomaly of cell 
x ) Sterility produced after exposure to X rays appears, according to the data 
at present available, to be due to azöospermia. A purely functional sterility caused 
by exposure to X rays, occurring wlien spermatozoa are still formed, does not appear 
to be met with. 
