34 SIXTH UEPOUT — 1836. 



adoption of an hypothesis, so strongly opposed to probability as 

 that advocated by Anglada, 



Those who are sceptical as to the possibility of so very rapid 

 and apparently so spontaneous a production of organic matter, 

 as that which takes place in these thermal waters, should peruse 

 a memoir in Schweigger's Journal^, and also one more lately 

 published in Poggendorff'sf, by the celebrated Ehrenberg, on 

 the blood-red appearances observed at various periods, covering 

 the surface of lakes and stagnant pools, spreading over various 

 articles of food, or descending in rain from the heavens. 



The former of these papers proves the rapidity with which 

 bodies of this kind are generated ; the latter establishes, that in 

 almost every case in which the particulars have been carefully 

 investigated, the pbaenomenon has resulted from the generation 

 of some kind or other of organic matter. 



There is, indeed, an observation of GimbernatJ, which ought 

 perhaps not to be passed over, although I am not myself dis- 

 posed to attribute any weight to it. I allude to his finding a 

 substance similar at least to glairine, if not identical with it, in 

 the condensed vapours proceeding from the fumaroles of Vesu- 

 I'ius. But when we recollect, that the apparatus in which this 

 steam was collected had been allowed to remain for one or two 

 days without being disturbed, during which time the water was 

 freely exposed to atmospheric influences, under circumstances 

 peculiarly favourable to the growth of Confervse, there seems no 

 necessity for supposing the organic matter found in it to have 

 been derived from the entrails of the volcano. 



I have myself collected, on several occasions, the vxipours that 

 arose from the spiracles of this very same mountain, after the 

 great eruption of ] 834, as I have stated in the memoir which I 

 published in the Philosophical Transactions ior 1835, but in no 

 instance could I discover any organic matter. 



Red ferru- I" the thermal springs of Vichy, and in some other localities, 

 ginous mat- where sulphur is not present, an organic substance has been 

 **''■ observed floating on the surface §. 



Longchan)p, in his account of that spring, states that it is in- 

 termixed with carbonate of lime, together with which I found 

 entangled within its meshes a portion of peroxide of iron j and 



• For 182? ; extracted from a work by Dr. Sette, entitled Mem. Storica 

 Naturale. Vcnezia, 1824. 



f Translated in Edinburgh New Philosophical Join-nal for 1830. 



X Bihliotheque Univeiselle, vol. xi. 



§ Vauquelin, Annales de Chimic, vol. xxviii. 



