214 THE ACTION OF THE LIVING CELL 



proteolytic organisms, shock does not usually follow 

 the injection of the tissue extract. 



Such experiments show conclusively that bacterial 

 infection may lead to cytost intoxication, provided the 

 infecting organism is capable of causing the libera- 

 tion of cytost from the infected tissue of the host. In 

 such a case, then, the host may sufifer from the sum- 

 mation of two harmful factors: the cytost liberated 

 by the activities of the organism on the tissues, and 

 the specific toxins elaborated by the bacteria them- 

 selves. On this basis it should be clear that if prior 

 to infection the animal has a high degree of resistance 

 towards cytost, it may suffer less from the action of 

 the infecting organism. 



In connection with some experiments upon the dif- 

 fusion of bacteria through the intestinal wall, the 

 writer (Turck, 1914) has made some interesting ob- 

 servations which indicate that the joint action of bac- 

 teria and cytost leads to a distinct potentiation of the 

 latter. Before discussing the reason for this, let us 

 consider the experimental findings. 



Dogs were opened under anesthesia, and a culture 

 was taken from the lumen of the intestines. The con- 

 tents (secretions) were removed from the duodenum 

 and jejunum, diluted with four volumes of normal 

 saline solution, and placed on ice until needed for 

 subsequent stages of the experiment. This extract 

 will be referred to below as S. The intestines were 

 then removed, and divided into two sections, the first 

 comprising the duodenum and upper jejunum and 

 the second the lower jejunum and ileum. The mucous 

 membranes were removed from these by scraping and 

 then ground with four volumes of saline. These ex- 



