On Spontaneous Generation. 623 



ing identical ; the vegetable tribes will present, in each re- 

 spectively, analogies of form and general character; but few, 

 if any, of the same species will be found in localities thus 

 separated ;" — there can hardly be brought forward an argu- 

 ment which proves more in favour of the generatio cequivoca, 

 for had plants been propagated on the surface of the earth 

 by gradual migration from one locality adapted to their na- 

 ture, to another, we should find the very same species in every 

 place that " exists under the same physical circumstances ; " 

 whereas we find only analogous plants in similar places, be- 

 cause, though there are many places in America much like 

 others in Europe, so far as geological and climatic conditions 

 go, yet the telluric influences are far from being identical ; 

 and we need only advert to the difference of situation with 

 respect to the magnetic poles to make this sufficiently appa- 

 rent. Yet these localities are quite as well adapted to pro- 

 pagating the species brought thither from similar localities. 



Nor do I see why the migrations of animals and plants, 

 which have retained their specific characters, from one con- 

 tinent to the other, and where human agency has been em- 

 ployed, can militate against the doctrine of spontaneous ge- 

 neration. Although, for example, the present continent of 

 Africa has not been able to produce a tapir, yet, if a couple 

 of this species were transported to some favourable locality 

 there, and to thrive and propagate, this fact could never be 

 brought forward as proving that the tapir might as well be an 

 aboriginal species of one continent as the other. 



I hope Mr. Blyth will allow that Cuvier's remark, — " La 

 vie exer§ant sur les elemens qui font a chaque instant partie 

 du corps vivant, et sur ceux qu'elle attire une action contraire 

 a ce produiraient sans elle les affinites chimiques ordinaires, 

 il repugne qu'elle puisse etre elle-meme produite par ces affi- 

 nites, et cependant V on ne connait dans la nature aucune 

 force capable de reunir des molecules auparavant separees," 

 cannot be fairly opposed to the grounds on which 1 have ven- 

 tured to support the generatio spontanea ; for I have dis- 

 tinctly alluded to that extra force of which Cuvier says we 

 know nothing, and cannot therefore be suspected of thinking 

 that the common chemical affinities can ever produce an or- 

 ganized body. We know that magnetism, galvanism, and com- 

 mon electricity, are either mere modifications of the same pow- 

 er, or determine each other : we know that there is a constant 

 electrical and magnetic tension, both in the solid crust of the 

 earth and in the atmosphere ; that the metallic veins (as shown 

 by Mr. I. W. Henwood), the plants, (as lately confirmed by 

 Mr. Golding Bird), and the animals (as proved by Mr. Mat- 



