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 ingesticm of powdered glass, chemical agents, and irritating bacteria, failed to show that 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, Beco2 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 iti 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 Ztitschrift fur Ifygiene, June 25, 1896, Bd. xxii., Heft I. 2 Ann. (te rinst. Pasteur, 1895, No. 3.