378 



SCIENCE. 



[N. S. Vol. XV. No. 375. 



Chromogenie bacteria, as B. pyocyaneus 

 and M. pyogenes citreus, however, failed to 

 produce pigment. On medium (B), made 

 of water 100 gms., peptone 6 gms., NaCl 2 

 gms., MgSO^ 0.3 gm., K,HPO 0.5 gm., 

 agar 2 gms., 15 varieties grew quicli:ly witli 

 the production of pigment and, in one case, 

 of phosphorescence. Then the peptone was 

 replaced by a non-albumenous compound, 

 such as ammonium salts or asparagin. On 

 medium (C) containing water 100 gms., 

 glycerin 50 gms., (NHJPO^ 10 gms., 

 Na,HPO, 1 gm., MgSO, 0.2 gm., agar 1 

 gm., 19 varieties grew rather slowly. On 

 imedium (D) consisting of water 100 gms., 

 asparagin 1 gm., NaCl 0.5 gm., MgSOj 0.3 

 gm., agar 1 gm., 9 varieties grew with no 

 formation of pigment. On medium (E) 

 consisting of water 100 gms., asparagin 1 

 gm., Na,PO, 0.1 gna., NaCl 0.2 gm., agar 1 

 gm., 20 different kinds of bacteria, mostly 

 pathogenic, grew as quickly as on the 

 standard media. 



Further experiments are now being car- 

 ried on and, in view of the fact that so 

 many bacteria can grow on this non-albu- 

 menous medium, it is probable that some 

 combination of simple chemicals can be 

 found that will replace the ordinary meat 

 infusion. A medium consisting of such 

 compounds, qualitatively and quantitative- 

 ly known, would be of great value in the 

 study of bacterial metabolism. 



A Tank for the Growth of Germs in Large 

 Numbers: Victor C. Vaughan, Ann Ar- 

 bor, Mich. 



Professor Vaughan, of the University of 

 Michigan, described an apparatus, devised 

 by himself, for the purpose of obtaining 

 bacterial cells in large quantity. A copper 

 tank ten feet long, two feet wide, and four 

 inches deep, with a trough around the edge 

 one inch deep, is covered by a top of the 

 same material. This tank is supported by 

 an iron frame with legs ten inches high. 



and the whole is placed on a table covered 

 with galvanized iron. A similar tank, two 

 inches shorter and two inches narrower, 

 also provided with a trough around the 

 edge and a cover, sets in the larger one, 

 and is separated two inches from the bot- 

 tom of the larger one by iron bars extend- 

 ing from side to side. The bottom of the 

 outer trough is filled with water, and the 

 seal trough of the outer tank is also filled 

 with water, while the seal trough of the 

 inner tank is filled with glycerin. Both 

 lids are raised and lowered by wire 

 ropes passing through pulleys in the 

 ceiling. It is necessary that the tanks 

 should be set perfectly level. Twenty li- 

 ters of two per cent, agar are placed in the 

 inner tank ; both lids are lowered, and with 

 large burners underneath the apparatus 

 becomes a sterilizer. After repeated steril- 

 izations, the upper lid of the outer tank is 

 raised and the agar inoculated by pouring 

 through tubular openings, in the top of 

 the inner tank, a liter of a beef-tea culture 

 of the germ. These openings are then 

 sealed with wax and the outer lid lowered. 

 With gentle heat underneath the apparatus 

 becomes an incubator. 



After the germ has grown for fourteen 

 days or longer in this tank, the germ sub- 

 stance can, by the addition of a little 

 water, be scraped from the agar, and from 

 each tank there may be obtained forty or 

 more grams of dried, pulverized germ sub- 

 stance. 



With the colon bacillus the following 

 facts have been learned concerning its tox- 

 in: (1) The toxin is contained within the 

 cell from which it does not, at least under 

 ordinary conditions, diffuse into the cul- 

 ture medium. (2) The toxin is not ex- 

 tracted from the cell by alcohol or ether. 

 (3) Very diluted alkalis do not extract the 

 toxin from the cell. (4) The germs may 

 be heated in sealed tubes with water to 

 184° for thirty minutes, without loss of 



