MODE OF SPREAD OF INFECTIVE DISEASES. 743 



branes and lymphatic glands, and ultimately reach the 

 blood. It is probable also that pathogenic bacteria behave 

 in this respect in the same manner as the ordinary in- 

 tants of the surface of the body; for the excreting 

 membranes of the animal body (kidneys) are just as 

 impassable for the numerous kinds of pathogenic bacteria 

 as for the saprophytic organisms. 



Nevertheless it was desirable to make direct experi- Direct experi- 

 ments as to the passability of the walls of the lungs and 



of the intestine by bacteria ; and experiments of this f the lungs 



. . x and the mtes- 



kind have been carried out in large numbers by Wysso- tine by 

 kowitsch during the course of last year in the author's bactena - 

 laboratory. From these experiments, which will be 

 shortly published in the Zeitschriftfur Hygiene, it follows 

 with complete certainty that neither the surface of the lung 

 nor of the intestine permits the direct passage of bacteria 

 into the blood, so long as the mucous membrane is intact; 

 even if small lesions of the mucous membrane are pre- 

 sent, the bacteria do not as a rule reach the blood, but 

 remain in the neighbouring lymphatic glands. In the Intestine. 

 experiments on the intestine, staphylococcus aureus, 

 bacillus indicus, and spores of subtilis were employed; 

 the cultivations were given in large quantities as food, 

 and it was found that the bacteria did not suffer any 

 injury from the gastric juice; but in order to be more 

 certain as to this point, they were in some cases injected 

 into loops of intestine isolated by ligatures. In no case, 

 however, were the bacteria found in the organs which, as 

 had been previously ascertained, always preserved any 

 germs which had really reached the blood; while, on the 

 other hand, they were always found when even only very 

 small quantities of the same bacteria were introduced 

 into the blood or into the peritoneal cavity. In the 

 experiments with loops of intestine, small injuries of the 

 intestinal membrane were unavoidable; and then the 

 bacteria in question could be found in limited numbers 

 in the corresponding mesenteric glands, but did not pass 

 beyond them.* 



* Eibbert (Deutsch Med.Woch., 1885, Nr. 13) andBizzozero (Centralbl. 

 f. d. iued.\\ r och., 1885, Nr. 45) found various kinds of bacteria in healthy 



