166 INTRODUCTION 



normal in the second tube containing complement only, agglutinated in 

 the last two. 



After forty-eight hours transfers are again made. The first tube always 

 remains sterile, the second is often sterile (3 times in 6), the last two give 

 agglutinated cultures. 



After three days the subcultures result as follows ; the first two tubes are 

 always sterile, the third often so (4 times in 6), the last always gives an 

 agglutinated culture. 



After four days the first three tubes are always sterile. The last tube 

 only, that is, the one containing both antibody and complement, gives an 

 agglutinated culture. 



After six days the same result is obtained. 



The same experiment has been performed with the Shiga dys- 

 entery strain and the anti-dysentery serum of the Pasteur In- 

 stitute. The result was in all respects comparable. The Shiga 

 bacillus, like the cholera vibrio, persists for a long time in the 

 suspension containing the anti-serum and the alexin. 



Variations in all directions have been made in the proportions 

 of the sera, both in that containing the complement, and in that 

 containing the antibody, as well as in the concentration of the 

 bacterial suspension. The results have all been essentially the 



centimeter, the sterilization is complete in a few hours at a temperature of 

 37C. On the contrary, these organisms will remain alive for some days 

 in tap water. And what is still more singular, is that everyone has adopted 

 physiological saline for the preparation of bacterial suspensions, concluding 

 a priori, that bacteria must be preserved alive for a long time in a medium 

 spoken of as "isotonic." 



At the bottom of this we find a false deduction by comparison. Eed 

 blood cells hemolyze in a few seconds in tap water, but, on the contrary, 

 they resist hemolysis in isotonic saline solution. Thus, it is concluded, 

 without doubt, that bacterial cells must conduct themselves in the same 

 manner. As a matter of fact, this is absolutely contrary to what takes 

 place. 



As we will see, the same reasoning has been held with regard to the so- 

 called bacteriolysis with sera. There also, one falls into an error, and this 

 will always be the case when an attempt is made to substitute deduction 

 based on analogy for experimentation, especially when the elements con- 

 cerned are as different as a bacterium and a red cell. 



With reference to the toxic action of sodium chloride, Loeb (Biochem. 

 Zeitschr., 1906, 2, 81) has shown that this salt may be toxic for all the 

 unicellular organisms living in the sea, and that this toxicity may be neu- 

 tralized by the salts of potassium and calcium. 



