oi)6 ON THE ORIGIN OF ENTOZOA 



little of this water to the eggs with a camel-hair pencil, they 

 were rendered equally fruitful with those which had been 

 fecundated in the usual manner. So, in other animals, we are 

 not ignorant of the means by which generation is effected ; and 

 in these a very small portion of semen only is conveyed to 

 the ovaris during coition. And when conception has taken 

 place, we observe that the ovum is latent during the first few 

 days, that it then appears very small, and at a later period 

 becomes an evident embryon. These facts being established, 

 we think that the opposite proposition is proved, viz. " the 

 Entozoa cannot be transferred to the ovules by means of the 

 male parent ;" for who would contend for the possibility of the 

 eggs of worms being contained in so small a quantity of semen? 

 or how could the eggs of worms, infesting the different regions 

 of the body, gain access to the seminal fluid of the parent ? or 

 supposing, for the sake of argument, that this is possible, how 

 are the germs of animals to become the recipients of parasitical 

 ovules of equal, perhaps superior, magnitude with themselves? 

 If, in addition to this, we remember, that many of the Entozoa 

 are viviparous, and that it is therefore physically impossible 

 that their embryones can be contained in the semen of the 

 parent, and that they can be thence transferred to the ova in the 

 ovaries of the female ; and with the knowledge that some worms 

 (as the Cysticerci) are solitary, never copulate, and therefore 

 produce no eggs, we shall be convinced of the falsity of this 

 hypothesis ; and it is unnecessary that I should give any further 

 illustration of my opposing arguments. All the objections 

 which are urged above apply with equal force to the following 

 hypothesis, and those which I am about to oppose to the latter 

 are equally fatal to the hypothesis just treated. 



Are they communicated by the female parent ? 



That the ova of worms are communicated by mothers to 

 their fcetal young, is a theory which Vallisnierus, Goeze, Bloch, 

 Werner, and nearly all helminthological authors, have warmly 

 supported, and pronounced indubitable. 



Those authors, indeed, who have been sensible of the diffi- 

 culties which surround this hypothesis, have not pronounced 

 it indubitable, but have rather embraced it as the most pro- 

 bable, seeing that all the other theories are untenable, and fall 

 short of solving the difficulty ; but I think they cannot have 

 deeply examined the nature of it. I find it surrounded with 



