zi 4 



THE QUARTERLY REVIEW OF BIOLOGY 



of the plant. The work of Allen, LaBach, 

 Pinnell and Brown is particularly illumin- 

 ating. 



Colin's (1915) experiments were con- 

 ducted with sterile water, into which 

 broth cultures of the test organisms were 

 introduced. Pressures varying from 10 to 

 Z4 kilos were then applied for varying 

 lengths of time, generally from one to 

 twelve hours. Bact. typhosum, Bact. coli, 

 Bact. dysenteriae (Shiga), V. choleras, Ps. 

 pyocyansa, C. diphthsriae and B. subtilis 

 were subjected to study under carbon 

 dioxide pressures. Sterilization was ef- 

 fected with Bact. typhosum in zo hours or 

 more at 10 kilograms C0 2 pressure. With 

 C. diphtherias sterilization was obtained at 

 10, 15, and zo atmospheres after 14, 9, and 

 3 hours respectively. Bact. coli persisted 

 for 5 days under 15 kilo pressure. 



In 191 1 another departure from the 

 study of the destructive effects of carbon 

 dioxide on bacteria occurred. Lieske 

 reported that Spirophyllum ferrugineum is 

 benefited by the presence of carbon 

 dioxide. The growth of the organism 

 was considerably increased by this gas, and 

 inhibited by the presence of organic 

 matter. 



Wherry and Oliver (191 6), following 

 Nowak's work of 1908, grew the gono- 

 coccus and several other organisms under 

 reduced oxygen tension. It was empha- 

 sized that some parasitic species could be 

 isolated or made to grow considerably 

 better under partial tension than under 

 full anaerobic or aerobic conditions. No 

 mention is made of carbon dioxide influ- 

 ence. Five bacterial species in all were 

 used, including Bact. typhosum. 



Cohen and Markle (1916) reported a 

 successful primary isolation of meningo- 

 coccus under partial oxygen tension, but 

 no mention is made of any possible 

 influence of carbon dioxide as such. 



Wherry and Ervin (1918) furnished some 



experimental data which indicated that 

 carbon dioxide is necessary for the growth 

 of M. tuberculosis. Saprophytic and non- 

 saprophytic strains were used in the 

 experiments, and were found to be alike 

 in their failure to grow in the absence of 

 carbon dioxide. 



Larsen, Hartzell and Diehl (1918), in 

 an effort to produce antigenic material in 

 a diffused state, resorted to high pressures 

 under various gases. Carbon dioxide was 

 fatal to Bact. typhosum, Bact. coli, M. 

 tuberculosis, Ps. pyocyanea, staphylococci, 

 streptococci and pneumococci in from 1.5 

 to z.5 hours. Pressures of carbon dioxide 

 under 40 atmospheres did not produce any 

 visible effect on the bacteria studied. 

 The action of this gas under pressure was 

 more destructive in distilled water than in 

 nutrient broth. Yeast cells resisted it 

 much longer than Z4 hours. 



BENEFICIAL EFFECT OF CARBON DIOXIDE 



Cohen and Fleming (1918) made use of 

 the tandem cultivation method in their 

 meningococcus studies; they also supplied 

 carbon dioxide gas as such, in amounts 

 varying from 10 to 75 per cent. Their 

 results showed that as good growth could 

 be obtained by supplying the gaseous 

 C0 2 as with the B. subtilis culture method. 

 The optimum concentration varied from 

 10 to 30 per cent carbon dioxide. With 

 from 50 to 75 per cent of the gas the 

 growth was scant. Their explanation 

 was that the C0 2 dilutes the oxygen and 

 thereby helps the growth; i.e., the partial 

 tension phase was strongly emphasized. 



In the same year (1918) MacKenzie 

 reported that zz per cent carbon dioxide 

 was bactericidal for the meningococcus 

 in Ringer-Locke solution, in zo minutes. 

 Ruediger (1919) confirmed the partial 

 tension idea by obtaining good growth of 

 the meningococcus in stoppered tubes. 

 There was no growth when the tubes were 



