66 The American Naturalist. [Tanuary, 



gradsky ; like his it is incapable of converting salts of ammonia into 

 nitrate, but unlike his is motile (when taken from colonies on gelatine 

 or silicates), stains readily, causes slow liquefaction of gelatine, and is 

 not yellowish but varies from colorless to bluish when grown on silli- 

 cates. The chemical activity is almost exactly the same as that of 

 Winogradsky's bacillus and these authors, who have been studying the 

 subject for two years, seem to think that it may after all turn out to be 

 the same organism, the differences being less important than would 

 seem at first sight, and resting perhaps on incomplete observations. 

 The most important distinction appears to be the ability of this organ- 

 ism to grow on organic substances, but it does not appear from Wino- 

 gradsky's publications whether he tried to transfer his organism from 

 sillicate-plate cultures to bouillon, or gelatine, and failed.— Erwin F. 



Relation of Sugars to the Growth of Bacteria.— Unques- 

 tionably the most discriminating and important paper that has yet ap- 

 peared on this subject is a recent one, Ueber die Bedeutung des Zuck- 

 ers in Kulturmedien fur Bakterien (Centrb. f. Bah. u. Par., Med., Bd. 

 XVIII, No. 1), by Dr. Theobald Smith, now of Harvard. Reference 

 is made to the literature of the subject but this is contradictory and 

 many of Dr. Smith's interesting conclusions are largely or wholly the 

 result of his own laborious and brilliant researches. The propositions 

 are stated clearly and it is safe to say that hereafter no one will un- 

 dertake the study of bacterial fermentation and gas production without 

 first consulting this paper. The author's summary is as follows, but 

 many things are not mentioned in this and the whole paper will repay 

 the careful perusal of all who have groped about in this field of bac- 

 teriology : (1) In ordinary meat bouillon, souring and gas formation 

 are only observed when sugar is present. Dextrose is the sugar most 

 commonly attacked and muscle sugar is probably identical with it. (2) 

 The formation of acid results from the breaking up of the sugar ; the 

 formation of alkali in the presence of oxygen results, on the contrary, 

 from the multiplication of the bacteria themselves. So far as tested, 

 the production of acid is common to all anaerobic bacteria (facultative 

 or obligate). (3) Facultative anserobiosis is made possible by the pres- 

 ence of sugar. (4) Rauschbrand and tetanus bacilli grew in fermenta- 

 tion tubes only when sugar was present. In test tubes containing the 

 same sugar bouillon multiplication was never seen. (5) As far as 

 tested, all gas-forming species produce along with C0 2 an explosive gas. 

 (6) Souring as well as the production of gas are valuable diagnostic 



