lyO DR. E. KLEIN. 



A mouse inoculated with a few drops of the uncompressed 

 solution died, and presented, as before, all the appearances of 

 splenic fever. 



Experimental Contribution to the Etiology of Infec- 

 tious Diseases with special reference to the Doctrine 

 of CONTAGIUM VIVUM. By E. KleiNj M.D,, F.R.S. 

 (With part of Plate XI.) 



Read before the Royal Society on February 17th, 1878. 



The present communication has for its object to bring 

 before the Royal Society the results of an experimental 

 inquiry' into the etiology of an infectious disease of the pig, 

 known as Hog Plague, Mai Rouge, Red Soldier, Malignant 

 Erysipelas, or also Typhoid Fever of the Pig. Their are 

 English and continental writers who descri1)e the disease as 

 Anthrax or Splenic Fever of the Pig. I shall show, how- 

 ever, conclusively in my Report to the Medical Officer of 

 the Local Government Board, that it is neither typhoid 

 fever nor anthrax, but is an infectious disease of its own 

 kind, which I propose to call " Infectious Pneumo-Enteritis 

 of the Pig" {Pneumo- enteritis contagiosa). 



Like other infectious diseases, the " Pneumo-Enteritis " 

 possesses an incubation period, followed by constitutional 

 disturbance and certain anatomical changes. These latter 

 are invariably affections of the lung, of the intestine, and 

 of the lymphatic glands, not only of those of the organs of 

 respiration and alimentation, but also those of the inguinal 

 and lumbar regions. In the lung the changes are those 

 known to pathologists as lobular pneumonia. In the ali- 

 mentary canal the mucous membrane of the large intestine 

 is chiefly affected, being the seat of smaller or larger ulcera- 

 tions. There is generally also inflammation of the serous 

 membranes, especially the peritoneum, leading to an exuda- 

 tion of Imph into the serous cavity. The skin is occasion- 

 ally affected with greater or smaller red patches. 



There are hajuiorrhagic patches to be found in the lung 

 and serous membranes, the endocard, and the muscle of the 

 heart, the mucous membrane of the intestine (especially 

 duodenum and large intestine), the tongue, and occasionally 

 also the liver and spleen, only seldom in the skin and kidney. 



In anatomical respects, therefore, the Pneumo-Enteritis 

 bears undoubtedly a great resemblance to anthrax or splenic 



' This beinnj part of a larger research carried out for the Medical 

 Officer of the Local Government Board. 



