400 On the Theory of the Fecundation of the Ovum. 



them, — calling up in them, by virtue of its own state, a chemical 

 movement which is in relation either to the composition of the 

 bodies themselves, or to the quality of the chemical movement 

 existing in the acting body. Thus, to take the commonest ex- 

 ample, the ferment of beer, being in a state of chemical move- 

 ment, induces the formation of alcohol in a saccharine solution, 

 without, however, the occurrence of any chemical combination 

 between the elements of the ferment and those of the sugar. 

 This is an attractive hypothesis, and the more so as there is not 

 perhaps a more general law in nature than that by which a body 

 in motion communicates a part of its motion to another body 

 with which it comes in contact ; and this is more considerable 

 in proportion to the amount of resistance offered by the second 

 body. According to Bischoff, the seminal fluid may be com- 

 pared to the yeast of beer, and the ovum to the saccharine solu- 

 tion. The former being in a state of chemical movement, would 

 induce in the second a series of modifications, commencing with 

 the segmentation of the vitellus up to the formation of the embryo. 

 After all, this would only be to place the phsenomenon of genera- 

 tion upon the same footing as that of digestion. In fact, whether 

 we call the substances actively in operation in digestion, ptyaline, 

 pepsine, pancreatine, or diastase of the saliva, of the stomach, 

 pancreas, &c., we are not the less obliged to recur to the force 

 of contact in order to account for their action. Bischoff 's ex- 

 planation was not very satisfactory, as long as it was believed 

 that the semen only came in contact with the membranes of the 

 ovum. But now that we know that the spermatozoa penetrate 

 into the interior of the ovum, either through the micropyle or 

 otherwise, and that when there they are in a state of chemical 

 movement (the fatty metamorphosis of Meissner), this theory is 

 far from losing probability. Nevertheless it is still nothing but 

 a theory, convenient it is true, but impossible to demonstrate. 

 That organized beings may be the products of a simple fermenta- 

 tion is possible, but we shall only attach positive credence to it 

 when we obtain palpable proofs of its truth. The force of contact, 

 again, is itself really nothing but the expression of the facts, and 

 not an explanation ; so that by Bischoff's theory the difficulty 

 is only removed a step backwards. We must leave the question 

 in doubt, impressed as we are with the feeling that great pre- 

 caution is required in applying purely chemical explanations in 

 such cases as the present, not merely to organic, but to organized 

 bodies. The existence of the micropyle and the penetration of 

 the spermatozoids into the ovules of organized beings are im- 

 portant discoveries ; but by these only a corner of the veil has 

 been raised, and the veiled image of Isis still leaves us many 

 mysteries to be revealed. Thus we believe we must for once 



