86 PRELIMINARY COLD STORAGE STUDIES. 



then for 7 days. Buchner's zymase was also tested and survived for 

 20 hours. Some photogenic bacteria exposed to this extreme cold 

 promptly ceased to emit light, but thawing soon caused a resumption 

 of activities. 



Macfayden says: "It is a remarkable fact that, notwithstanding 

 the enormous mechanical strain to which the organisms must have 

 been exposed, a strain far exceeding in amount any capable of being 

 produced hitherto by direct mechanical means, not the slightest 

 structural alteration could be detected." There was no impairment, 

 according to the observations of this author, in the vitality of the 

 organisms. Belli a has also subjected the bacteria of chicken cholera 

 and anthrax to the action of the temperature of liquid air, without 

 altering their properties. 



DEVELOPMENT OF BACTERIA AT LOW TEMPERATURES. 



At temperatures approaching the zero point not only viability but 

 fertility has been proven, and the literature shows that quite a num- 

 ber of investigations have been conducted, and the field is wider than 

 would at first sight appear. Forster, 5 for example, finds that certain 

 photogenic bacteria grow at 0° C. and that organisms capable of 

 developing at this temperature are to be found in earth, milk, 

 flesh, spring water, etc. He also states that the plague bacillus is 

 capable of growing at zero. He determines, too, the rate of growth 

 in an ice calorimeter, and finds that from 10 to 12 days are usually 

 sufficient. Discussing the question of bacterial growth in the 

 German " Kuhlhaus," Forster c concludes that the changes induced are 

 slower than at ordinary temperatures, but are not stopped nor essen- 

 tially altered. S. Schmidt-Nielsen d found five species of bacteria 

 which developed at zero in the Strassburg water supply, from 10 to 40 

 days being required for appreciable growth. He found, also, an 

 actinomyces which required 80 days for development. 



These organisms are Bact. fluoresceins nonliquefaciens , B. granu- 

 losum, B. paracoli gasoformans anindolicum, B. tarde fluorescens, and 

 B. radiatum. Fischer e and Havemann f have also studied organ- 

 isms which are capable of making a growth at zero, the former iso- 

 lating fourteen species from various sources and the latter obtaining 



aRiforma Medica, 1901. 



& tiber einige Eigenschaften leuchtender Bakterien, Zentrbl. Bakt. Paras., 1892, 12: 

 431. 



c tlber die Entwickelung von Bakterien bei niederen Temperaturen, ibid., p. 431. 



d Uber das Vorkommen psychrophiler Bakterien, Zentrbl. Bakt. Paras., 1902, 9: 145. 



« Bakterien Wachstum bei 0°, etc., Zentrbl. Bakt. Paras., 4: 89. 



/ Inaug. Diss. Rostock, 1894, Uber das Wachstum von Mikro-organismen bei Eis- 

 schranktemperatur. 



