The Conditions of Infusorial Life. 93 



of infusoria is not dependent npon germs contained in solid 

 bodies. 



With reference to the water and its action, M. Ponchet elu- 

 cidates it by experimenting with an artificial combination of 

 oxygen and hydrogen. Having obtained a sufficient quantity 

 of water in this manner, he boiled half of it to destroy any 

 germs that might have fallen into it, and then made an infusion 

 with some hay that had been heated to about 200° centigrade. The 

 whole was covered with a bell-glass, and in a few days displayed 

 two species of paramecia. The other half of the artificial water 

 was treated with hay that had been heated, and yet the same 

 infusoria appeared. These experiments, says M. Pouchet, prove 

 that water is not the receptacle of the " germs" on which his 

 opponents rely. They merely show that water containing no 

 germs will suffice as a medium in which germs from some other 

 source may be developed. Another illustration of the action of 

 water was obtained by skimming off, from an infusion of China 

 aster, " an immense quantity" of kolpods, which were transferred 

 to distilled water, and remained in perfect health for fifteen 

 days ; from which M. Pouchet concludes " that it is not the 

 matter dissolved in the water which feeds the microzoaries, or 

 at any rate they can live a long time in pure water." Another 

 curious experiment was performed by grinding up with a muller, 

 or pestle, a legion of kolpods. One half of the homogeneous 

 paste thus obtained was diluted with water, filtered, and placed 

 under a bell-glass; the other half was mixed with the same 

 quantity of water, but not filtered. In a week of moderate 

 temperature, the filtered water exhibited an innumerable quan- 

 tity of vorticellids, and not a single kolpod ; while the non-filtered 

 mixture displayed no vorticellids, and no kolpods, but small 

 monads. Upon these facts our author remarks, " The partisans 

 of the transmission of eggs through the intervention of atmos- 

 pheric air, cannot in any way explain what happened in these 

 two experiments. If the two vessels had contained kolpods, the 

 supporters of ovarism would have declared that the eggs of 

 these animalcules were so small that the grinding process had 

 not broken them up." From a single experiment of this sort 

 no general conclusion can be drawn ; but, as we shall presently 

 see, there is no reason to believe that the air contains an un- 

 limited supply of germs of all sorts : one portion will contain 

 none at all ; another, those of a particular kind, while a third 

 will differ from the other two. Speaking of the minuteness of 

 certain animalcules, M. Pouchet quotes Owen, to the effect that 

 a single drop of water may contain more monads (M. crepus- 

 culum) than there are human beings on the globe; and he 

 adds, but this microzoary can manifest itself wherever we offer 

 it appropriate infusions, and that on the aerial diffusion theory, 



