36 Rev. P. Keith on the Conditions of Life. 



with today. But the contrary of all this is the fact. The 

 species are not interminable, but circumscribed, and in some 

 of them the mode of propagation has been actually ascertained. 

 But animalcules have been found in infusions that have been 

 boiled, roasted, and even subjected to the heat of a blowpipe ; 

 and this has been regarded as a proof that they have not pro- 

 ceeded from anything possessing life. Yet some species of 

 seeds will survive even the action of boiling, and their germs, 

 as we may suppose, are not less vivacious than themselves ; and 

 if the infusions in question were deprived of everything vital, 

 whence came the animalcules? — They must have come from 

 without. They must have penetrated the containing vessels ; 

 — a fact which cannot be admitted without due evidence. 

 Fray affirms that he found animalcules in mineral mixtures * ; 

 and the same doctrine has been again advanced by Brownf, 

 who finds them in rock, glass, ashes, soot, when ground to 

 an impalpable powder and mixed with a little water. But as 

 this question may be said to be yet sub judice, we will adopt 

 the proposition of Cuvier, and say with him, " La vie ne nait 

 que de la vie J," — Life originates only in life. 



This proposition has been a good deal carped at, unfairly, 

 as we think, by Barclay^, who disapproves of the doctrine 

 which it contains altogether, and asks whether the first indivi- 

 dual, or the first pair of any species, could have come into ex- 

 istence in this manner ? — The answer is ready. Cuvier's ob- 

 ject was not that of tracing phaenomena to their first causes, 

 which may lie concealed for ever from human view, but merely 

 to such causes as fall within the sphere of human observation, 

 and are cognizable by human means. This is philosophy ; 

 this is physiology. The study of a first cause is religion ; and 

 our knowledge of it is derived, chiefly, from revelation. We 

 do not say that it must necessarily be excluded from physio- 

 logical research; but if the individual inquirer chooses to ex- 

 clude it for the purpose of keeping separate two subjects that 

 are perfectly distinct, he is not therefore to be regarded as an 

 atheist. What light has Dr. Ure thrown on geology by his 

 boasted introduction of the agency of a first cause ? — But, says 

 Barclay, what are we to make of the animalcula itt/'usoria ? 

 It has not been proved that they are the product of generation ; 



* Essai sur I'Origine des Corps organises : Barclay. 



t [Justice to Mr. Brown requires from us a remark on this point. It will 

 be found, on perusing that gentleman's papers on Active Molecules (Phil. 

 Mag. and Annals, N. S., vol. iv. p. Ifil, vi. p. ICl), that he nowhere ascribes 

 animal life to them, as the cause of their motion, and consequently ought 

 not to be stated as regarding them to be animalcula. In the latter paper, 

 indeed, he has expressly denied that he considers the active molecules to 

 be animated. — Edit.] 



X Lemons d'Anat, Compar, : Barclay. § On Life and Organization. 318. 



and 



