146 
THENOGENESIS, 
these eggs.’ In some of them he says he found as 
many as three, and in twenty-four only one. He sub- 
sequently carefully examined eggs taken from drone 
cells, treating them in the same manner, and says that 
he ‘ did not find one seminal filament in any single 
egg, either externally or internally.’ 
It is possible that Siebold may have found more 
than one spermatozoon in some of the eggs, and until 
recently it was believed that more than one might 
enter the ovum, but Geddes and Thomson ( 45 ) 
point out that — 
‘Researches such as those of Hatwig and Fol have 
shown that when one sperm has found admittance, the 
way is usually barred against all others. The micropyle 
may be blocked, or the surrounding membrane may be 
altered, or in other ways the ovum may exhibit what 
Whitman calls ‘ self-regulating receptivity,’ so as to be no 
longer penetrable. We are safe in concluding that the 
ovum is usually receptive only to one sperm ; that in 
most cases the entrance of more than one sperm is 
impossible.’ 
Why and how the spermatozoon finds its way to 
the micropyle is involved in mystery; but Geddes and 
Thomson (45) point out that the theory of Rolph is 
being accepted as the most probable one, namely, 
that ‘ the less nutritive, and therefore smaller, hungrier, 
and more mobile organism ’ (cells, he is speaking of) 
‘ we call the male ; the more nutritive, and usually more 
quiescent organism is the female ; ’ and he goes on 
to suggest why ‘ the small, starving male cell seeks out 
the large, well-nourished female cell for the purpose of 
