28 SPONTANEOUS GENERATION OF PLANTS 



Art. V. — On the Flora of Snow Formations, in reference to the 

 theory of Spontaneous Generation. By W. Weissenbobn, 

 Ph. D. 



Although the recent discoveries of Professor Ehrenberg 

 appear little favourable to the casual production of organic 

 beings at the present period, yet they do not in the least 

 affect the theory, that their original existence is owing to a 

 purely dynamic process. The importance of this subj ect will 

 perhaps excuse me if I try, in this place, to lessen the weight 

 of the above conclusion,' by some reflections (founded on 

 facts to which I have not alluded in my former articles on this 

 question) on certain spontaneous generations which are un- 

 doubtedly going on in our time, and which, in calling the at- 

 tention of the reader to the traces of a nascent future creation, 

 may serve to throw some light on the conditions of the former 

 and present ones, as well as to banish the uncouth idea of a 

 Deus ex machina. 



Although it would appear from the calculations of M. Fou- 

 rier, as applied by M. Arago (Annu. du Bur. de Long. 1834), 

 that the general temperature of the globe has not changed by 

 ■i^ of a degree centig. within the last 2000 years, yet, accord- 

 ing to the theory of cosmogony now universally admitted, the 

 body which shall next add a new crust to the solid part of our 

 planet must be water, in the various modifications of structure 

 which it presents under the forms of ice and snow. What 

 proportion of the existing quantity of it w ill be required and 

 consumed in completely oxidizing and cicatrizing the actual 

 mineral crust, it is impossible to determine ; but leaving the 

 vapoury part of it out of the question, and supposing the mean 

 depth of the ocean to be only four miles (the calculations of 

 Laplace make it from four to five), and its extent about three 

 fourths of the surface of the globe ; then supposing the mean 

 density of the solid and lasting products of water, from the 

 hardest ice to the lightest snow, to be half that of water, the 

 thickness of the strata that will be added to the globe by the 

 solidification of the water existing on the surface of our pla- 

 net will be six miles. Were the bed of the ocean to remain 

 in its present state, the present mineral crust of the globe 

 would be covered only three miles high, reasoning from the 

 present level of the sea; but as that bed is constantly filling 

 up, the distribution of the crust of ice and snow over the whole 



» The conclusion alluded to will be found in Vol. 3, paffe 508, in an 

 analytical notice of Ehrenberg's work.— Ed. 



