Developmental History of Infusorial, Animal Life. 363 



error : the membrane which seemed to form itself round the 

 starch granule had quite another origin. He observed the 

 little Monads swimming about, and noticed one of them adhere 

 to a starch grain, spread its elastic body round it, and finally 

 envelope it, just as the Amteba does its food. Thus was 

 explained how the starch grain came to be inside a cell ; and as 

 this process was never suspected, and as the starch-grain was 

 within a cell-wall, the idea of natural formation was inevitable, 

 the more so as the wall seemed to grow larger and larger. 



M. Pasteur, who has been the leading and most determined 

 opponent of the spontaneous generation theory, contrived a 

 series of experiments which met many of the arguments 

 brought forward by Pouchet, and he thought it was possible to 

 obtain, in some place, atmospheric air so pure that it would 

 not produce any change whatever in a putrescible liquid. M. 

 Pouchet, Joly, and others, in their desire to meet this idea, as- 

 cended the glacier of La Maladetta, in the Pyrenees, taking with 

 them a number of flasks, each one third filled with an infusion 

 of hay, which had been previously filtered and boiled for more 

 than an hour. The air was then exhausted, and the flasks 

 hermetically sealed. Pour were then afterwards filled with air 

 on the . surface of the glacier, and four in a crevasse. The 

 examination of four of the flasks, three days afterwards, gave 

 specimens of Bacteria, Monads, Vibrio, Mucidinea, and Amaiba. 

 The conclusion drawn from this was that even the air of high 

 mountains did not fulfil the conditions which M. Pasteur pre- 

 dicated of it. Nevertheless M. Joly said that he believed that 

 M. Pasteur was quite right in his statement that all that was 

 required for the production of animalcules was ' f air and a liquid 

 susceptible of putrescence, " and that in his opinion there is no 

 such thing as " spontaneous generation. - " 



M. Pasteur goes on to state that the doctrine of spontaneous 

 generation may be expected to be constantly turning up, since 

 it maintains a hold over us, unknown to ourselves, from its 

 relation to the impenetrable mystery of the origin of life upon 

 the surface of the globe. Gay Lussac's report of his examina- 

 tion of the method of preserving provisions for the army, was 

 not without its influence on the minds of men on the subject 

 now under consideration. He proved that when the air in the 

 bottles in which substances have been well preserved is 

 analyzed, it no longer contains oxygen, and consequently that 

 the absence of that gas is a necessary condition for the conserva- 

 tion of animal and vegetable substances. He also found that 

 grapes crushed under mercury do not undergo fermentation 

 unless brought into contact with pure oxygen, or with common 

 air, even in a scarcely perceptible quantity. Such experiments, 

 made with so much exactness and care by so great a master of 



