HERBERT C. WARD 9 



show evidence of enzymic activity even when no evidence of germination is present. 

 Oxidases as well as gelatinase can be demonstrated in spore material. Magoon' be- 

 lieves that spores are not dormant under ordinary conditions but are sluggishly ac- 

 tive. Resistance to heat is not fixed but variable, being influenced by age, tempera- 

 ture, heredity, etc. This resistance to heat may be increased by selective action (Ma- 

 goon).^ In Bacillus mycoides certain organisms surviving after heating seem to have 

 greater resistance to heat than the original spores. Daranyi^ has recently pointed out 

 that the ability of certain species like Bacillus anthracis, Bacillus subtilis, and Bacillus 

 anthracoides to form spores depends in general upon the same optimum conditions which 

 lead to good vegetative development of the bacteria. Spore formation is brought 

 about primarily by colloidal reactions; the most important of these is a diminution in 

 the water content of the organisms, resulting therefore in a shrinking of the colloids. 

 Under natural conditions spore formation begins when the organisms grow older. 

 This aging is primarily a loss in water on the part of the colloids (hysteresis). The 

 lack of food material for the bacteria has a favorable influence on spore formation only 

 in that the organisms get poorer in water. With artificial dehydration, Daranyi was 

 able to bring about spore formation in well-developed young bacilli. 



Koser and McClelland^ have added interesting facts in regard to the fate of spores 

 in the animal body. The spores of Clostridium tetani, CI. putrificmn, CI. chauvei, and 

 CI. oedematis-maligni are capable of withstanding the deleterious influence of the body 

 tissues and may be transported from the site of inoculation to different organs, where 

 they remain latent. Aerobic bacteria do not apparently suffer the same fate. Such 

 observations are of considerable importance in an explanation of the occurrence of 

 tetanus after wounds in cases where the wound itself is originally uninfected; it is pos- 

 sible that the latter infection is due to the presence of latent spores in other parts of 

 the body. Finally, mention must be made of the newer methods of determining the 

 heat resistance of spores. Esty and Williarass have estimated resistance by heating a 

 large number of tubes containing spores and plotting curves from the results. The 

 rate of destruction corresponds in general to the rate of destruction of bacteria by dis- 

 infectants worked out by Chick, by Madsen and Nymen, and by Eijkman. 



MULTIPLICATION IN THE SPIROCHETES 



The flexible spirochetes differ considerably in their morphology from the simpler 

 bacteria but not sufficiently to separate them from the group in which the first repre- 

 sentative was placed originally by Ehrenberg. In at least three particulars is their 

 morphology interesting to us at the present time — their motility, method of division, 

 and the possession of granules which are occasionally extruded from the cell and 

 which may be reproductive bodies. In regard to motility it has now been satisfactorily 

 proved that the spirochetes possess no organs of locomotion like flagella, as was orig- 

 inally maintained. Flagella-like structures may occasionally be found, attached to the 



' Magoon, C. A.: ibid., ii, 253. 1926. 



^Magoon, C. A.: /. Infect. Dis., 38, 429. 1926. 



3 Daranyi, J.: Centralbl.f. Bakteriol., Abt. II, 71, 353. 1927. 



* Koser, S. A., and McClelland, J. R.: /. Med. Research, 37, 259. 1917. 



5 Esty, J. R., and Williams, C. C: /. Infect. Dis., 34, 516. 1924. 



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