ZOOLOGY. 395 



containing organic matter is placed, one of them hermetically sealed, the other 

 left open to the air. They are then placed in a bath of boiling water, and kept 

 there till their temperature has reached that point. After this, they are left 

 undisturbed for a few days. In the tube which was exposed to the air, there 

 were animalcules; in the tube Avhich was excluded from the air, before the 

 action of heat had destroyed all the germs, not an animalcule could be seen. 



Is not this something like a proof? "Why, no, sir," as Johnson would 

 have said. At least, not if the argument previously urged is worth any- 

 thing. Because every one will see that if it be true, as Milne-Edwards main- 

 tains, that the temperature of boiling water is not by any means high enough 

 to destroy the organic germs of animalcules, then it could not have destroyed 

 those germs in the closed tube, and animalcules ought to have made their ap- 

 pearance thei-e. If I could lay any particular stress on my own experiments 

 (which I do not), they would lead to the conclusion that the organic germs 

 do not resist the action of boiling water; for I found that a piece of fish, 

 divided into three, and placed in boiling water in three different tubes, one 

 closed and excluded from the light, the second closed but exposed to the 

 light, and the third open and exposed to the light, gave me no animalcules 

 at all : had there been any germs in the water or meat, these must have been 

 destroyed. But all such observations go for nothing in the presence of M. 

 Poucliet's assertion that he had found animalcules in the infusion, after sub- 

 jecting the organic matters to a temperature of two hundred and fifty de- 

 grees Centigrade (five hundred and forty-six degrees Fahrenheit), and this, 

 too, with artificial water. Unless the germs are supposed to be incombusti- 

 ble, it is difficult, he says, t6 maintain, after this, that the animalcules were 

 developed from germs. 



Milne-Edwards being thus disposed of by M. Pouchet, let us see how M. 

 Quatrefages will come off. He says that, having examined the dust remain- 

 ing on the filter after some observations on rain-water, he found that the 

 organic elements presented a confused assemblage of particles; and this 

 continued to be the case for a few minutes after their immersion in water. 

 But a few hours afterwards, he detected a great number of vegetable spores, 

 infusoria, and those minute, spherical, and ovoid bodies, familiar to inicro- 

 scopists, which inevitably suggest the idea of eggs of extremely small di- 

 mensions. He also declares that he has frequently seen monads revive and 

 move about after a few hours of immersion. The conclusion drawn is, that 

 the air transports myriads of dust-like particles, which have only to fall into 

 the water to appear in their true form of animalcules. 



The reply of M. Pouchet is crushing. If the air is filled with animalcules 

 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 substances in 

 decay, the half dozen will be free from animalcules and eggs, but the one 

 will abound with them. Now, it is perfectly intelligible that, inasmuch as 

 organic matter is said to form the indispensable condition for the develop- 

 ment of the eggs, it is only in the vessel containing such matter that the 

 eggs will develop ; but why are they not also visible as eggs in the other 

 vessels? why are not the animalcules themselves visible there, as they were 

 in the water examined by M. Quatrefages? If both eggs and animalcules 

 are blown about like dust in the air, it is an immense stretch of credulity, to 

 believe thcv will be blown into the vessel containing organic matter; but the 



