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bearing upon the pathological problems involved. One of 

 the things which most strike the student of Pasteur's work 

 and that of his followers is the remarkable variety of condi- 

 tions under which microbe life is apparently carried on. 

 Here again it seems as though life was the dominant force 

 in the universe which moulded almost any conceivable con- 

 ditions to its use. " You have discovered," said Dumas to 

 Pasteur, "a third order of beings in animated nature — 

 creatures who can live either with or without free oxygen." 

 Following up the experiments of Pasteur demonstrating the 

 existence of life outside the conditions which mankind had 

 come to regard as essential to life, and resulting in his classi- 

 fication of germs as anaerobies and aerobics, we have had a 

 most astonishing series of observations. Semper has called 

 attention to the fact that far higher forms of life, than we 

 assume the micro-organisms to be, actually do live under 

 gaseous conditions which would be fatal to the higher verte- 

 brata, and that the capability of breathing assumed poison- 

 ous gases varies greatly in different animals. The mere 

 inference by Pasteur that each form of fermentation has its 

 peculiar ferment implies the existence of life under a most 

 extraordinary variety of chemical conditions. Dr. Miquel 

 has cultivated a bacterium which has the singular power of 

 transforming sulphur into sulphuretted hydrogen and which 

 apparently lives and prospers in a milieu charged with 

 sulphuretted hydrogen gas. The same experimentalist is 

 sure of at least one bacillus whicli lives and multiplies in 

 solutions heated to a temperature of from 70 to 72 deg. C, 

 or 15 degrees above the temperature assigned by Cohn as 

 the limit beyond which, though spores may retain latent the 

 power of germinating, no actual growth or multiplication by 

 scissiparity or spore production can take place. Van 

 Tieghem professes to have carried the limit within which 

 vegetation is possible up to 74 deg. C. We have further the 

 experiments of the lamented Frank Hatton on the cultiva- 



