FERMENTATION BACTERIOLOGY. 913 



FERMENTATION— BACTERIOLOGY. 



The bacterial air flora of the semidesert region of Nev^ Mexico, 

 J. Weinzirl {Jour. Cincinnati Soc. Nat. Hist., 19 (1000), JVo. 7, pj). 

 211-243, f(/s. Jf; Science, n. ser., 12 {1900), No. 303, pp. 578, 579).— K 

 study of the uir flora of the semidesert region of New Mexico was 

 made b}" exposing pctri plates for 10 minutes. The number of plates 

 exposed at one time was usually ;^>, the results given being averaged. 

 Seventeen exposures were made near the University of New Mexico 

 l)etween September and May. An average number of bacteria falling 

 upon the plates was 35.8. The lowest number, 3.8, was observed in 

 February, and the highest, 71, in September. Quantitative determi- 

 nations were made of the bacteria, and 11 determinations gave 143 

 ))acteria per cubic meter. The bacteria found represented 14 species, 

 6 of which were chvomogenetic. Four of these are micrococci, the 

 remaining colonies being all bacilli. 



The conclusions reached are as follows: 



" (1) The air bacteria of our .semidesert region presents a somewhat Hmited flora; 

 but this is found to be widely distributed, due undoubtedly to the high winds which 

 sweep uninterruptedly over our wide stretches of nearly barren mesas. 



" (2) The actual number of bacteria contained in the air is not as large as in fer- 

 tile and cultivated regions, but the number is not as small as is popularly supposed. 



" (3) It would seem to follow from the above that sanitary measures and pre- 

 cautions should receive practically the same attention here as elsewhere. Disease- 

 bearing materials, such as infected clothes, sputum, etc., should be carefully disin- 

 fected or burned. 



" (4) ilany of the species show highly-colored colonies; these belong mostly to 

 the group of micrococci. The flora is characterized by its inertness toward sugar 

 media and its failing to peptonize gelatin. 



" (5) Apparently none of the species have been previously described." 



The influence of the temperature of liquefied air on bacteria, 

 A. Macfadyen and S. Rowland {Proc. Boy. Soc. \ London], GO {1900), 

 Nos. It.20,pp. 180-182; 1^30, pp. 339,3 Ifi). — Experiments are reported 

 in which 10 species of bacteria were exposed for 20 hours to the tem- 

 perature of liquefied air ranging from —182 to —190^ C. The cultures 

 of the organisms were vigorous and were tested in both solid and fluid 

 media. After they had been exposed to the temperature of the lique- 

 fied air, they were carefully thawed and examined. In no instance, 

 whether on solid or liquid media, could any impairment of the vitality 

 of the micro-organisms be detected. A second experiment was per- 

 formed in which 50 liters of laboratory air, taken about 6 ft. from the 

 floor, were liquefied, the temperature reaching about —210° C. Plate 

 cultures were made from the contents of the bulb which had contained 

 the liquefied air and were grown for a period of 10 days. The anae- 

 robic plate cultures remained sterile while the aerobic plates yielded 

 44 organisms which had survived the exposure to —210° C. 



In a second paper on this sul)ject the authors, instead of exposing 



