THE BACTERIAL ENDOSPORE 55 



conclusion; in that, Martin and Foster-^, when they studied the 

 incorporation of various types of labeled compounds into DPA, 

 obtained little evidence for the incorporation of succinate. In 

 their experiments there may have been an abundant supply of 

 succinate within the cell, and therefore, it did not utilize succi- 

 nate added from the outside. You may recall from data on the 

 anaerobic culture, that we could separate the formation of the 

 heat-sensitive spore from the synthesis of DPA and from the 

 development of heat resistance. We have not been able to 

 obtain such a separation in the case of the aerobes. We have, 

 therefore, investigated other inhibitors to see if we could find 

 some substance that would permit the synthesis of the spore 

 structure but not the synthesis of DPA, and thus prevent the 

 production of a heat-resistant spore. We have succeeded in 

 obtaining this result with two inhibitors, ethyl oxamate and 

 diethyl pimelatc. 



To pursue this study one needs some mechanism to differen- 

 tiate between heat sensitive spores, vegetative cells, and germi- 

 nated spores. In this case, it cannot be done by heating. Octyl 

 alcohol proved to be suitable for this purpose. This alcohol is 

 very toxic to vegetative cells, killing them almost instantly, and 

 also will destroy germinated spores almost equally fast. Spores 

 are extremely resistant to this chemical, and, as will be shown 

 later, the heat sensitive spores are also resistant. Table IX shows 

 the effect of octyl alcohol upon germinated spores and vegetative 

 cells of B. cereus. Table X shows the effect of ethyl oxamate 



TABLE IX 



EFFECT OF OCTYL ALCOHOL ON THE VIABILITY OF SPORES, GERMINATED SPORES, 



AND VEGETATIVE CELLS OF B. C ere US T. 



Without octvl alcohol With octvl alcohol 

 Type of cells ^.^^j^ ' Heat stable Viable 



Spores 3 x 10^ 2.5 x lO^ 3 x 10« 



Germinated spores 1.6 x 10^ 10^ 10^ 



Vegetative cells 6 x 10' <100 <100 



References p. 59 



