210 INFECTION AND IMMUNITY. 



rather than to the usual serum agglutinin. Becht 

 and Greer find that agglutinins occur in the var- 

 ious body fluids in the following order of concen- 

 tration : blood serum, thoracic lymph, neck lymph, 

 traces in the pericardial fluid, least and not con- 

 stantly in the cerebrospinal fluid and aqueous 

 humor. The administration of pilocarpin causes 

 a rise in the agglutinating power of the tears, 

 sputum and some other body fluids; the drug 

 increases cell secretions. 



inheritance. When typhoid fever occurs during pregnancy, 

 agglutinins may appear in the serum of the fetus. 

 On the one hand it has been held that agglutinin 

 passes from the mother to the fetus, or, on the 

 other hand, that the presence of agglutinins arises 

 from infection of the fetus itself. 



Although the milk may be very rich in agglu- 

 tinin, it is doubtful if the serum of a breast-fed 

 child undergoes much increase in its agglutinating 

 power because of the ingestion of the milk. The 

 intestinal juices (trypsin) digest agglutinins. 



The origin of agglutinins in the animal body is, 

 according to very convincing experiments of 

 Hektoen and Carlson, the tissue cells of the body. 



significance One of the most interesting and important phe- 



of Agglnti- . , , , n . ., . f, T, n 



nation, nomena in the study of immunity is the so-called 

 Pfeiffer phenomenon. An animal which has been 

 rendered immune to cholera by repeated injections 

 of cholera vibrios has the power of digesting or dis- 

 solving the latter when they are placed in the fresh 

 serum or in the peritoneal cavity of the immunized 

 animal. Gruber and Durham were studying this 

 phenomenon in the test tube when they first ob- 

 served the agglutination reaction. It was found 



