THE QUARTERLY REVIEW OF BIOLOGY 



these experiments, since carbon dioxide 

 was applied at atmospheric pressure. 

 The experiments as a whole offer only a 

 very limited amount of data. 



BACTERIA IN CARBONATED WATERS 



Hochstetter's work (1887) was on the 

 behavior of microorganisms in artificial 

 carbonated waters, city water of Berlin 

 and distilled water. This work has 

 remained as a source of valuable informa- 

 tion, and has probably not been surpassed 

 in extent and comprehensiveness. The 

 experiments included pure culture studies 

 of M. aurantiaca, E. prodigiosus, pink 

 yeast, a green fluorescent bacillus, a 

 yellow bacillus, M. tetragenus, Bact. lepi- 

 septicum, B. anthracis (vegetative cells and 

 spores), Bact. typhosum, alpha-bacillus, 

 V. cholerae, spores of Aspergillus flaves- 

 cens, and Finkler-Prior's bacillus. These 

 organisms fell into three groups, according 

 to their tolerance for carbon dioxide: 

 (1) those which were viable for only a 

 short time, (Y) those which remained 

 viable for a few weeks, and (3) those 

 which survived for many weeks and even 

 months. 



According to Hochstetter's observations, 

 there is no danger from cholera through 

 carbonated waters, but the danger from 

 typhoid fever is not altogether removed, 

 since Bact. typhosum remains viable for 

 from five to seven days. Epidemics of 

 typhoid traced to carbonated waters 

 occurred in Mainz in 1884. The author 

 was able to control the development of 

 bacteria in experimentally carbonated 

 waters. Numerous organisms were found, 

 however, in bottled beverages prepared 

 under factory conditions. 



Sirotinin (1888) reported a limited 

 number of trials with V. cholerae, the 

 Finkler-Prior spirillum, Staph, albus, B. 

 anthracis, B. cuniculicida and Bact. murisepti- 



cum. There was complete inhibition of 

 the last two organisms. 



Frankel (1889) reported a comprehen- 

 sive series of experiments comprising forty 

 different bacterial species. Gelatin me- 

 dium was used in Esmarch tubes, and 

 carbon dioxide gas was applied while the 

 medium was still soft. It is noteworthy 

 that inhibition or even killing was 

 obtained with the organisms which are 

 very sensitive to acid, for example V. 

 cholerae. His observations were briefly 

 summarized as follows: Certain common 

 types of bacteria were able to develop in 

 carbon dioxide as well as in the ordinary 

 atmosphere; others were retarded, and a 

 third group would not grow at room 

 temperature, but would develop in C0 2 

 at higher incubation temperature. The 

 effect of carbon dioxide was also tried on 

 the saprophytic bacteria. The influence 

 was not wholly inhibitive. The author 

 believed that his results may be taken as 

 a proof that carbon dioxide is a preserva- 

 tive or germicide. He stated at the same 

 time that, in spite of this growth-inhibit- 

 ing, or at times even killing, action, carbon 

 dioxide should not be regarded as a sure 

 means of preventing decomposition. 



Weakening of pathogenic bacteria by 

 C0 2 does not occur, according to him. 

 The author also pointed out that in view 

 of the unhindered growth of Bact. typho- 

 sum in a stream of C0 2 , the so-called 

 "harmlessness" of carbonated waters must 

 be liberally interpreted. 



Frankel's work is similar to Hoch- 

 stetter's in comprehensiveness, and, al- 

 though conducted in a somewhat differ- 

 ent manner, the conclusions arrived at 

 are identical. Frankel also observed that 

 the reaction of the gelatin medium 

 changed under the stream of carbon 

 dioxide. He believed, however, that 

 this change in reaction was inconsequen- 



