ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 91 



ductive of bacteria than five times its proportion of atmospheric dust ; 

 in the latter case the forms are chiefly Bacterium lineola, in the 

 former B. termo ; this difference bespeaks a different origin for the 

 two growths. 



Solution of sugar and the microcosmic salt and coal-ashes in dis- 

 tilled water produced no bacteria in 28 hours after addition of dust, 

 and but few when left to itself, but with a drop of bacterian liquid it 

 contained abundance, arranged in tracts ; in 45^ hours the condition 

 was essentially the same, but after 68 hours the dust preparation 

 contained an abundance in masses ; also the uninfected solution, but 

 here development appears to have begun four or five hours later than 

 in the dust preparation. 



Pieces of an almond more than two years old were boiled for a 

 minute in distilled water, and the decoction put while hot into 9 watch- 

 glasses, " cleaned, as usual, as well as possible," and covered up. The 

 contents of these glasses were variously treated, with the following 

 results : — 



No. 1. Left untouched ; developed a yeast-fungus and some mycelia, 

 after the lapse of 2 2 days. 



No. 2. Similarly treated; was filled with mould and fermentation 

 fungi after 13 days. 



Nos. 3, 4, and 5, having received, the one 2 grams, the other a 

 drop of distilled water, the third a drop of emulsion of almond kernel 

 in distilled water, were clouded with a minute bacterium in 48 hours. 



No. 6 received two pieces of almond, and began to be clouded 

 with a bacillus in 70 hours. 



No. 7, infected from an emulsion full of bacteria, swarmed with 

 the same form in 24 hours. 



No. 8, which had received a few milligrams of atmospheric dust, 

 showed some larger bacteria, some being united into rods and chains, 

 after 44 hours. 



No. 9 was infected with a dried-up drop of bacterium liquid, and 

 became cloudy in 40 hours. 



From these and similar experiments Krasan concludes, first, 

 that heat disorganizes the molecules of organic substances so as to 

 render them incapable of becoming rearranged into organic structures 

 without the stimulus of fresh air or other agents; secondly, this 

 stimulus need not proceed directly from organic germs strictly so 

 called, but may just as well be derived from the fresh air itself. 

 Water and various liquid and solid organic substances are employed, 

 which are either unaltered by heat, or else have been long in contact 

 with fresh air. 



Krasan considers the possible inorganic origin of low organisms 

 absolutely proved by his finding them developed first in the Micro- 

 coccus-, then the Zoogloea-form. in a precipitate of calcium phos- 

 phate in calcium sulphate solution to which sugar had been added ; 

 he has observed them to arise from minute granules which occur in 

 the freshly formed precipitate, and considers it due to decomposition 

 of the sugar molecules and recombination of their radicals with the 

 other constituents. 



