Developmental History of Infusorial, Animal Life. 361 



the action of the direct rays of the sun, it has been kept in the 

 dark, and sometimes has been for a year or two in a Very dry 

 place without a particle of water touching its surface. To 

 amuse friends I have again and again allowed a little water, 

 sometimes filtered, generally of the coldest spring nature, to 

 fill up the space between the two glasses — water I had previ- 

 ously tested for any living organisms. I have never failed to 

 produce, in a few hours, a most beautiful exhibition of one of 

 the most interesting species of Infusoria, having beforehand 

 sketched the exact creature I would produce. With the same 

 water, in another e-lass tank of the same nature but not so 

 prepared, I fail to produce anything at all until it has been 

 left for some days, and then the creatures seen are not my old 

 friends. I have read, not seen, that these organisms retain 

 their vitality even when the glass has been made red hot. I 

 don't say I believe, but from what I have seen I think it quite 

 possible/'' 



I have myself found, upon subjecting the spores of Penicil- 

 lium to the action of boiling water, twice over, that they 

 remain uninjured, their vitality is so little impaired that on 

 placing some of them in saccharine solutions and other sub- 

 stances, carefully excluded from the air, a very short time 

 sufficed to show the presence of the characteristic mould grow- 

 ing up from the spots where the spores rested, and micro- 

 scopic examination confirmed the character of the growth. 



M. Que,trefages says, that he examined the dust remaining 

 on the filter after ignition from some observations on rain- 

 water, and found that the organic elements presented a con- 

 fused assemblage of particles, and this continued to be the case 

 for a few minutes after their immersion in water ; but in a few 

 hours he detected a great number of vegetable spores, infusoria, 

 and those minute spherical and ovoid bodies familiar to micro- 

 scopists, which inevitably suggest the idea of eggs of extremely 

 small size. He also declares that he has frequently seen 

 monads revive and move about after a few hours immersion.* 



M. Pouchet's reply is, that if the air is filled with animal- 

 cules and their eggs, they will, of course, fall into any vessel 

 of water, and as water is their natural element, will there 

 exhibit their vitality. But if half-a-dozen vessels of distilled 

 water, perfectly free from animalcules, be left exposed to the 

 air beside one vessel of distilled water containing organic 

 matter in decay, the half-dozen will be free from animalcules 

 and eggs, but the one will abound with them. Now it is per- 

 fectly intelligible that inasmuch as organic matter is said to 



* Mr. Samuelson examined the dust shaken from rags brought from Alex- 

 andria, Trieste, Tunis, Peru, and Melbourne, and found in all germs of Monads, 

 Bacterice, and Kolpoda. 



