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4. The properties of the maternal ovum, receiving the ex- 

 traneous influence just mentioned, commence the processes which 

 terminate in the establishment of fetal life. As the maternal 

 ovum was indisposed for these processes previously to fecunda- 

 tion, so they must be considered as the result of a constitution 

 which lakes place in the ovum. 



5. As it is proved that the material and chymical parts of 

 the ovum are not the governing but the governed,* so the con- 

 stitution which takes place, sub coitu, and which produces the 

 changes hinted at, respects the properties of the organic spirit of 

 the ovum, and not its material alliances. 



6. It has been said that the properties of the maternal ovum 

 correspond either identically, or predisponently, with those of the 

 mother: the proofs of which are chiefly rested upon the following 

 description of facts : 



1st. The offspring of a black man and a white woman is a 

 mulatto. 



2nd. The offspring of a horse and an ass is a mule, &c. 

 Examples of this kind are familiar and the law obtains as far as 

 the procreative intercourse between varieties of the same species 

 is known to take place. 



7. Hence it appears, that as much as has been remarked of 

 the properties of the maternal ovum may also be said of the semi- 

 nal constitution, viz. that this likewise contains an organic spirit; 

 that this organic spirit is, like the maternal ovum, indisposed for 

 the changes which end in foetal life; that it exhibits in its ma- 

 terial aggregation but few properties; that it has many latent 

 ones, which correspond either identically, or predisponently, with 

 those of the subject in which it resides; that these latent proper- 

 ties are in peculiar combination, &c. A parity of laws may be 

 remarked between the seminal production and the maternal 

 ovnrn, because these laws are deduced, with but few exceptions, 

 and those of no great importance, from the same facts. 



8. But this subject, viz. the fecundated ovum, brings us to a 

 question which, in speaking of the maternal ovum, it would have 

 been anticipating the subject to have discussed fully. The ques- 

 tion is, whether the identical organic properties of the parent 

 reside in the ovum? or, whether its properties are only a predis- 

 position to those of the mother, existing in the several structures? 

 The same question, in the other case, may be tranferred to the 

 cause of fecundation. 



9. This question must be determined by our principles of 

 causation. The properties, whether of the maternal ovum, or of 

 the seminal fluid, never singly commence the processes which 

 end in fcetal life. It appears, therefore, probable that the pro- 

 creative rudiments, respectively, furnish only one stage of predis- 

 position towards the properties which form bone, muscle, &c.; but 



Book Second, Chapter I. 



