Xll GLOSSARY 



Macrocytase. In Metchnikoff's phraseology, the digestive enzyme secreted by 

 the large mononuclear leucocytes, and having a special action on cells 

 rather than on bacteria ; really a synonym for alexin, especially for one 

 acting on cells or red corpuscles. 



Macrophage. Metchnikoff's term for a large phagocyte which, according to 

 him, is especially adapted to the ingestion of cells or corpuscles rather 

 than of bacteria They may be large lymphocytes, large hyaline cells, 

 endothelial or other tissue cells. 



Microcytase. The digestive enzyme of Metchnikoff's microcytes or poly- 

 nuclear leucocytes ; supposed to have a special action on bacteria. 

 Practically identical with alexin. 



Microphage. A small leucocyte supposed by Metchnikoff to be specially 

 active against bacteria, and to have little or no phagocytic action on cells 

 or corpuscles. They are polynuclear leucocytes. 



Negative phase. The sudden diminution in the amount of an antibody (and 

 possibly of other defensive substances) in the blood which follows 

 immediately on the injection of an antigen. 



Neisser-Wechsberg phenomenon. Deviation of the complement, q.v. 



Nephrotoxin. A cytotoxin specific for renal cells. 



-ogen. A suffix usually employed to denote an antigen in relation to its anti- 

 body e.g., agglutinogen, the substance which on injection into an 

 animal leads to the production of agglutinin. Also used for a preliminary 

 non-active form of an active substance e.g., opsoninogen, a substance 

 which under certain conditions becomes opsonin. 



-oid (eldos, a figure or appearance). A suffix denoting a secondary modifica- 

 tion of an active substance in which it appears to retain its power of 

 entering into combination with its antibody or antigen, but has lost its 

 specific activity ; a molecule of antigen or antibody which has lost its 

 ergophore, but retained its toxophore, group e.g., complementoid or 

 toxoid, q.v. 



Opsonin (opsono I cater for, I prepare for food. Derived from &\}/ov, cooked 

 meat, a sauce or relish). A substance or combination of substances of 

 whatever nature which has the power of combining with a bacterium, 

 cell, or other substance, and rendering it more easily ingested by a 

 leucocyte or other phagocyte. 



Passive immunity. Immunity due to the injection of serum from an animal 

 which has acquired immunity to a toxin or infective agent. 



Pfeiffer's phenomenon. The classical Pfeiffer's phenomenon consists in the 

 globular transformation, loss of staining reaction, and finally complete 

 disappearance of cholera vibrios, when introduced into the peritoneal 

 cavity of an immunized guinea-pig, or into that of a normal one if 

 immune serum be also injected. Also applied to the similar, but usually 

 less complete, destruction of other bacteria under similar conditions, or 

 to bacteriolysis in general. 



Phytotoxin. A poisonous substance formed by one of the higher plants, but 

 otherwise closely resembling a bacterial toxin, more especially in its 

 power to give rise to the production of an antitoxin on injection e.g., 

 ricin, abrin. 



Polyceptor. Amboceptor which possesses several haptophore groups capable 

 of anchoring several molecules of different sorts of complement, the 

 most important of which is termed the dominant (Ehrlich). 



Polyvalent serum. A serum containing antibodies against several strains of 

 the same species of bacteria e.g., streptococci. 



Polyvalent vaccine. A vaccine composed of the dead bodies of several strains 

 of the same bacterial species. A vaccine composed of more than one 

 species of organism is termed a mixed vaccine. 



Positive phase. The period during which the amount of antibody or other 

 protective body in the serum is increased owing to the injection of an 

 antigen. In general terms it corresponds to the period of exalted im- 



