46 MICROBES AND TOXINS 



have prophesied fifty years ago that the removal of the 

 appendix would become as simple an operation as the 

 extraction of a tooth ? 



From the scientific point of view it is quite legitimate to 

 conclude that in a mammal so advanced in evolution as is 

 civilised man, both life and digestion are possible in the absence 

 of a large intestine. 



Is the Intestine Permeable for Microbes ? — There 

 exist in the massive flora of the intestine, bacteria both actually 

 and potentially pathogenic. After a wound which penetrates 

 the intestinal wall, the bacteria, which were harmless while in 

 the alimentary canal, invade the general peritoneum and cause 

 a fatal peritonitis. Immediately after death the intestinal 

 bacteria invade all the tissues and begin the work of putre- 

 faction. To prevent this happening during the lifetime of the 

 animal it is obviously necessary for the intestine to be 

 impermeable, and this impermeability must be due to the 

 living healthy mucous membrane. 



This opposing force is sometimes thrown out of action. 

 There are certain diseases which can only be explained by 

 supposing that the pathogenic bacterium has passed from the 

 intestine into the blood and into the organs. In hog-cholera, 

 which is caused by a virus still unknown, the lesions of the 

 lung contain a microbe which develops under cover of the 

 true virus and forms a regular complication in this disease. 

 This microbe is a normal inhabitant of the intestine of healthy 

 pigs. In all infectious diseases in which infection occurs by 

 ingestion, and which are not exclusively confinSd to the 

 alimentary canal, it is necessary to suppose that the microbe 

 passes from the intestine into the blood either directly by the 

 capillary vessels of the mucous membrane or by the more 

 roundabout way of the mesenteric lymphatic glands. Typhoid 

 fever, for example, is mainly a disease of the intestine, an 

 enteritis, but during the whole course of the fever the bacillus 

 circulates in the blood, and occasionally forms colonies in 

 distant organs such as the lungs and the bones. 



A very simple explanation suggests itself: the intestinal 



