432 EDWARD E. WILDMAN 
ROLE OF THE REFRACTIVE BODY 
In our search for the nature and function of this unique struc- 
ture, a review of the normal behavior of the Ascaris spermatozoon 
will be of interest. So far as we know at present, these cells 
are injected into the distal end of the uterus at the time of cop- 
ulation, and have to make their way to the proximal region of 
this organ by their own powers of locomotion, for the unferti- 
lized eggs are to be found only at the proximalend. ‘The uterus 
is usually not less than 12 and may be more than 15 cm. in 
length, and it is always full of eggs and developing larvae. The 
spermatozoa have, therefore, a relatively long and difficult jour- 
ney to accomplish; and since their only, known method of loco- 
motion is amoeboid creeping, their rate of travel must be very 
slow. Indeed, the total distance to be traversed by them is 
far greater than the length of the uterus, because the inner walls 
of this organ are thickly studded with epithelial papillae, so that 
their course cannot be a direct one. It is evident, therefore, that 
a considerable amount of energy must be expended by the sperma- 
tozoa in making this journey, and hence a definite food supply 
is necessary for their use. 
A very brief examination of the sperm which have reached 
the proximal or ‘entrance region’ of the uterus shows a great 
variation in the form and size of the refractive body, as we have 
seen. While Van Beneden interpreted these various shapes as 
indicating different stages in the growth of this structure, basing 
his opinion upon the hypothesis of the uterine origin of it, Mayer, 
Romieu, Romeis and others interpret them as stages in the pha- 
gocytosis or degeneration of superfluous spermatozoa. I believe, 
however, that they merely mark the normal consumption of a 
proper food supply by the spermatozoon itself. While figures 
40 and 48 represent sperm in which very little change in the 
form of this body has taken place, such are rare. In figures 
40, 46 and 47 are shown those in which only a remnant is left in 
the form of a corroded axial rod.7. In figures 39, and 41 to 45 
7 Since iron hematoxylon used after any acetic fixative stains both the inner 
and outer parts of the refractive body blue-black, it is an excellent stain to use 
to reveal even slight traces of this structure. 
