37*2 On Spontaneous Generation. 



farther than we can, nor prefer to seek for more positive cer- 

 tainty in gratuitous assertions. No one, I hope, will suppose 

 for each of the geological epochs, which had a creation of its 

 own, subsequent to the general incandescence and oxidation 

 of the globe's surface, a Dens ex machind, or a sort of Pro- 

 metheus, who manufactured the different animals and plants 

 severally by mechanical means. But unless we thus create 

 God in our own images, or make unto us graven images, we 

 feel compelled to suppose that there was a period in each ge- 

 ological epoch, when most of their respective organic beings 

 took what is called a spontaneous generation, from the re-ac- 

 tion of different kinds of matter upon each other, in conse- 

 quence of the inherent qualities and powers with which they 

 were invested, through the omnipresence of the Creator. — 

 This view appears to be not only the most rational one, but 

 its perfect accordance with what is still going on in nature 

 may be amply proved. 



This leads us to the latter part of the question, for the so- 

 lution of which we may draw upon human experience, though 

 the remote causes of the phenomena be quite as unfathomable 

 and mysterious, and in short the same, as those of the former. 

 We may, however, here trace the effects we observe, with more 

 precision, to their immediate causes. But before I commu- 

 cate a number of facts, which may contribute to establish our 

 conviction as to what has passed and is still passing on the 

 surface of the globe, I shall try to establish the general truth 

 of the principle, by what we observe in the most perfect of 

 its productions. 



Man has been most appropriately called the microcosm, 

 and as to the subject here under consideration, this qualifica- 

 tion may be vindicated to him as fully as in any other respect. 

 His organism is most productive of spontaneous generations, 

 answering to the three kingdoms of nature. Some of these 

 productions make their appearance in consequence of his na- 

 tural and regular developement ; others only appear in certain 

 human bodies, or at no particular stage of man's progressive 

 developement, and may be considered as anomalous or inci- 

 dental. To the former belong the following animals: the 

 Pediculus capitis humani, because their spontaneous genera- 

 is avoided only by the cleanliness employed by man in a ci- 

 vilized state. All savages are covered with this parasite, 

 and if any healthy person be confined to his bed, by some 

 local accident, as a broken leg, for a period exceeding five or 

 six weeks, and under circumstances which prevent him from 

 adhering to those habits of cleanliness to which he may be 

 accustomed, his head will be at once covered with adult 



