BIOLOGY OF BACTERIA. 59 



are ready for absorption. It seems probable that the 

 absorption of the toxic substances by reducing the vital- 

 ity of the individual predisposes to the formation of local 

 lesions through which the bacteria may 'enter the intes- 

 tinal walls to continue their existence and produce 

 greater damage than before. Some such theory may 

 explain the activity of such organisms as those of 

 typhoid, cholera, and meat-poisoning, but it is not true 

 that all bacteria can be admitted into the intestinal struc- 

 ture in this way, for the experiments of Max Neisser, 1 who 

 fed mice, guinea-pigs, and rabbits upon a variety of 

 pathogenic and non-pathogenic bacteria, both before and 

 after injuries to the intestine caused by the ingestion of 

 powdered glass, chemical agents, and irritating bacteria, 

 failed to show tliat with the exception of those bacteria 

 whose particular tendency is toward the production of 

 intestinal disease, none entered either the chyliferous 

 system, the blood-vessels, or the organs. 



The occurrence of the staphylococcus aureus and other 

 bacteria in osteomyelitis, and of tubercle bacilli in deep- 

 seated diseases of the bones and internal organs, has led 

 many to believe that the intestine is a point of easy 

 entrance. There is, however, no reason to believe that 

 penetration of the digestive mucous membrane is any 

 easier than that of the respiratory or other similarly deli- 

 cate tissues. 



On the other hand, Beco 2 is of the opinion that, with- 

 out any apparent lesion of the intestine, bacteria ba- 

 cillus coli escape from it into the blood during life. 

 His experiments showed that immediately after death the 

 colon bacillus could be found in small numbers in the 

 spleen, in many cases. After twenty-four hours, in 

 three cases, they were present in immense numbers. 

 When, however, they were absent from the organ im- 

 mediately after death, they were also absent after twenty- 

 four hours. 



1 Zeitschrift fur Hygiene, June 25, 1896, Bd. xxii., Heft I. 



2 Ann. de rinst. Pasteur, 1895, No. 3. 



