290 THE AMERICAN MONTHLY [December, 



of pyrogallic acid to 15 ccm. of i in 10 potash solution are suf- 

 ficient to extract all the oxygen. 



Colonies of anierobic micro-organisms are said to thrive very 

 well in this apparatus and are quite easily isolated. The appa- 

 ratus has the further advantage that the grow^th of the colonies 

 is easily examined through the thin bottom and their shape 

 studied just as in Petri's flasks. If the pyrogallate solution is 

 shaken up occasionally the absorption of the oxygen is accelerated. 



Growth of Bacteria on Acid Nutritive Media. — The 

 most prevalent notion as to the reaction of cultivation media is 

 that an alkaline or neutral reaction is almost absolutely necessary. 

 In order to show^ that an acid reaction is not so very inimical to 

 bacterial growth, I have made a series of experiments with some 

 of the best known bacteria such as Bac. typhosus, Bac. anthracis, 

 Staph, pyogenes aureus, Friedlaender's pneumonia-coccus, the 

 coccus of erysipelas, and others. The basis of the medium was 

 ordinary gelatin or isinglass mixed with 1.25 grm. pepton, 1.25 

 grm. NaCl, and 250 grm. water. To this mixture I add acids 

 (lactic, tartaric, citric, acetic, hydrochloric) or alum in various 

 degrees of concentration. The cultivations are made in test-tubes 

 at temperatures varying from 16° to 23°. 



The results, carefully tabulated and recorded, amount to this, 

 that a large number of bacteria grow on acid media, some indeed 

 very well, provided that a certain degree of acidity be not ex- 

 ceeded. The maximum acidity of the medium I have found to 

 vary extremely for each different species. The only schizomycete 

 which would not grow at all on any acidified was the micrococcus 

 of erysipelas, while the Bacillus atithracis grew even when the 

 medium contained 0.2 per cent, of lactic acid, and with 0.2 per 

 cent, of alum its growth was better and more rapid than on neu- 

 tral media. Nor was the virulenceof the anthrax diminished, as 

 proved by inoculation experiments on mice. 



It appears that the biological characteristics of some fission 

 fungi- are brought out very clearly on acid media ; among these 

 may be mentioned the bacillus of typhoid and the bacillus of blue 

 milk; the latter grown on isinglass decoction, to which 0.2 per 

 cent, of lactic acid has been added, develops its well-known pale 

 blue hue, a phenomenon which does not occur on alkaline sub- 

 strata. — Herr G. Schliiter^ in Ceiitralbl. f. Bagterioi. u. 

 Parasitenk.. xi {j8g2). 



MICROSCOPICAL NEWS. 



Mr. E. H Griffith, the well-known microscopist, and family 

 have located in Chicago, 111. Their present address is 5656 

 Washington avenue, that city. 



Washington Microscopical Society, for the cultivation and 

 advancement of microscopical science, filed articles of incorpora- 



