Cell Changes in the Tostis (lue to X Rays 
269 
X ray injuries is at present necessarily limited and imperfect, nevertheless 
owing to the important bearing which such investigation appears likely 
to have upon the numerous cytological observations which liave of recent 
years been made in connection with various pathological conditions, 
natural or induced, in particular in relation to mahgnant growth, it 
appears desirable to refer here, so far as this is possible, to the functional 
aspect of the structural changes observable after exposure to X rays. 
deferring for future consideration the interpretation of several problems 
in respect of which our observations are still in progress but are in too 
incomplete a condition to render discussion at this stage profitable. 
The seminal cells appear to be directly affected by X rays 1 ). The 
action of these rays if sufficiently intense and prolonged is to cause 
cell death, which is not, however, indicated by any immediate change 
(in the case of spermatocytes of the first order and spermatids) 2 ) but is 
revealed at the end of twenty four hours or more, when changes due 
presumably to ferment action have taken place, by general cloudiness 
and altered staining reaction, to which condition the term necrosis is 
applied. That in such cases complete arrest of function has from the 
first occurred is highly probable, since the cell elements do not exhibit 
any of the structural changes which attend the slighter degrees of appli- 
cation of X rays. 
Interest is centred however not in the action of X rays in amount 
sufficient to cause complete arrest of cell functions, but in that sufficient 
to cause only partial disturbance of cell function revealed later by struc- 
tural changes in the cell, for it is only in the latter case that individual 
cell elements are likely to be more or less exclusively affected, in which 
case important light may be expected to be thrown upon cell changes 
which are at present obscure. This, it may be observed, has been the 
object and has formed the starting point of the present investigation. 
The functional disturbances revealed by the structural changes 
x ) Secretory and nutritive functions have been attributed, as already mentioned, 
to the cells ef Sertoli. If this is so it is conceivable that such functions might be in- 
liibited by the action of X rays, and that some of the changes exliibited in the seminal 
cells might be the result of such inhibition. The extent to which such action may occur 
does not appear to be capable of estimation. On the other hand the rapidity with 
which cell destruction follows the application of X rays of sufficient intensitv and 
duration appears to afforcl conclusive evidence of the direct action of the rays upon 
seminal cells. 
2 ) We have not been able to observe this change in spermatogonia, spermato- 
cytes of the second order or spermatozoa. Cells of Sertoli are remarkably resistant 
to the action of X rays, being in this respect comparable to surface epithelial cells, 
