322 The Origin of Infusoria. 



tiling else to be done than simply to acquiesce in the results of 

 M. Pasteur, notwithstanding his scientific eminence and skill. 

 Nor is it true, as Dr. Sharpey appears to conceive, that the 

 presence of germinal spores in the atmosphere, sufficient to 

 account for the appearance of infusoria in solutions, has been 

 ascertained. M. Pasteur certainly discovered some spore-like 

 bodies, but we believe he never identified any of them as eggs 

 of infusorial animals. Professor Wyman states as the result of 

 many examinations of dust deposited in attics, and of the par- 

 ticles floating in air and collected on glass-plates covered with 

 glycerine, that like Pouchet, he found grains of starch, and 

 spores of cryptogams, and much less frequently what appeared 

 to be eggs of invertebrate animals, but that " both eggs and 

 spores may be said to be of rare occurrence.'" It will, how- 

 ever, be asked whether the eggs of infusoria could be discoverd 

 by the methods employed. M. Balbiani gives a table (which 

 will be found at the close of this article) of the number and 

 dimensions of the ova produced by various animalcules, and 

 as will be seen on reference to our account of his remarks in 

 No. 6, p. 468, he describes them as so transparent that their 

 form can only be made out by employing dilute acetic acid to 

 augment their cohesion and refractive power. It would pro- 

 bably be impossible, especially without the employment of re- 

 agents, to see those bodies after they had been caught in a 

 film of glycerine, or still worse, in one of olive oil which MM. 

 Joly and Musset employed, and we should certainly not be 

 warranted in assuming the non-existence of infusorial ova in 

 consequence of the failure of a comparatively clumsy means 

 of investigation. 



With reference to the appearance of Bacteriums or similar 

 objects in infusions apparently free from living germs of any 

 kind, we may observe that scarcely anything is known concern- 

 ing these minute organisms. Ehrenberg placed them among the 

 animals, and inferred their possession of a plurality of stomachs ! 

 Other investigators regard them as vegetables, and Mr. H. J. 

 Clark, of Cambridge, U. S., claims some of them as nothing 

 more than portions of decomposed muscular fibre or tissue. 

 Probably these objects, which assume the form of exceedingly 

 minute chains, more or less flexible and moveable, differ widely 

 in their real nature, and some of them may not even be alive at all. 



M. Pouchet now deposits with the French Academy a fresh 

 batch of printed and MS. matter on Heterogenesis, to compete 

 for the Alhumbert prize, and MM. Joly and Musset send in 

 for the same purpose their Nouvelles Etudes sur V Heterogenic, a 

 brief account of which is given in Gomptes Renclus, September 

 22, from which we select the most interesting facts. They took 

 a series of flasks holding one litre, and containing forty grammes 



