in the uterus (supposing the ovum to be a mere nidus of no specific 

 properties, capable only of inheriting what is imparted to it), for 

 then the placenta would stand a good chance of being the foetus, and 

 a polypus would inevitably put in for the same honour. Besides, the 

 properties of the cause of fecundation are found to be conferred 

 upon the ovum, which are alone sufficient to establish its character 

 as something more than a mere nidus, into which the properties 

 which it afterwards exhibits are gradually transfused; for the inter- 

 course between the ovum and the male has ceased with the act of 

 fecundation. 



30. Having now to speak of the influence which the spirit 

 exerts on the grosser materials of the ovum, in the course of its 

 progress to the next stage of its existence, it is proper that we 

 should examine, in the first place, by what kind of relation spirit is 

 able to produce those effects upon matter which have been all 

 along attributed to it. 



31. The spirit has been said to be identified by its properties, 

 by the causes which make it, and which then extend their opera- 

 tions to things subjected to them, and with which they are allied. 

 We will first connect the question with some general instances of 

 constitution, of which process the one we are considering is, among 

 others, an example. Why does the ink with which I write adhere 

 to the paper, and why would it not adhere to it if the paper were 

 oiled? Why does an acid combine with an alkali and make a 

 neutral salt? Why do vegetables derive nourishment from the 

 earth and not from stones? Why does the needle follow the load- 

 stone, or a man feed upon beef? It must be answered, from the 

 force of causes. All these are effects, to which causes impel; 

 existence, forcing existence. But the name of this process will be 

 inquired for: and surely it will be said the mode of causation is 

 not the same in this confusion of examples. We will return to the 

 examples and ascertain this point. 



32. Why does the ink adhere to the paper, &c.? it will be 

 said, by arj attraction of some sort or other; and when it is oiled 

 why does the ink run off? because there is no attraction, but rather 

 a repulsion; and why does an acid unite with an alkali, &c.? be- 

 cause there is ah attraction among the minute particles, so that they 

 are intermixed, past individual recognition^. And the other instances, 

 the loadstone and the needle, and the man and the beef, &c.? 

 attraction, if will be replied. And what is this attraction? a ten- 

 dency among substances to unite, of which there are various de- 

 grees and modes; but attraction is only one word, and expresses 

 this tendency to unite. 



33. Is this attraction, this tendency of things to contact, mix- 

 ture, union, &c. an identical principle; is it the same in all in- 

 stances? Why, truly, no: things that are joined together agree, 

 however different they might he else, in being joined together; so far 

 the effect is alike. So all things in the world exist; but because they 

 have this quality, or effect, in common, it does not follow that allthc 



