88 PATHOGENIC BACTERIA. 



The observations of Adami 1 indicate that the liver 

 constantly excretes or destroys bacteria absorbed from 

 the intestine. 



Weleminsky 2 found that the mammary glands some- 

 times participate in micro-organismal excretion, Bacillus 

 pyocyaueus making its appearance in the milk in from 

 five to eight hours after injection into the circulation. 

 He concludes that only those bacteria that produce le- 

 sions of the mammary gland are eliminated in the milk. 



The principal excretions with which bacteria are 

 eliminated from the blood are those of the mucous mem- 

 branes, the bile, and the sweat ; in diseased conditions 

 in the urine when the renal epithelium is damaged and 

 in the milk when the mammary gland is diseased. 



Bacteria are also discharged from the body in vast 

 numbers in pathologic discharges, such as pus, sputum, 

 and urine from the diseased animal. 



Special Phenomenon of Infection. — Agglutination. 

 — The phenomenon of agglutination was first observed 

 in connection with typhoid fever in 1896 by Widal and 

 Griinbaum. The phenomenon soon became known in 

 its typhoid fever relation as the "Widal reaction." It 

 consists in the cessation of motion of the bacteria and 

 the aggregation of the micro-organisms into clusters or 

 groups — agglutination — when a small quantity of blood 

 from an infected animal is added to a fresh active culture 

 of the specific organism. In many cases the substance 

 of the bacteria seems shrunken and the form distorted. 

 The bacteria are not killed as a rule. 



As the subject is of chief interest in connection with 

 typhoid fever, now being used every day for the clinical 

 diagnosis of that disease, much space will be devoted to 

 it in the chapter upon that subject. 



It is not by any means a typhoid fever reaction, how- 

 ever, but a widespread phenomenon of infection, having 



1 Jour. Amer. Med. Assoc, Dec, 1899. 



2 LXIV Versamml. der deutschen Naturforscher und Aerzte, Braunschweig. 

 Centralbl. f. Bakt. u. Parasitenk., April 16, 1898, xxiii., No. 15, p. 657. 



