GLOSSARY 



Active immunity. Immunity due to an active struggle against some infective 

 material, vaccine, or toxin. 



Addiment. See Alexin or Complement. 



Agglutinin. A specific antibody which brings about agglutination i.e. , 

 causes the bacteria, cells, etc., for which it is specific, to collect into 

 clumps. Non-specific substances (acids, etc.) have a similar action, but 

 are not properly termed agglutinins. 



Agglutinogen. The antigen of agglutinin i.e., the substance which, when 

 injected into a s Stable animal, leads to the formation of agglutinin. 



Agglutinoid, A modification of agglutinin which has retained the power of 

 uniting with the specific bacteria, etc., but has lost that of causing them 

 to clump. 



Aggressin (aggrcdior, I attack). A substance secreted by bacteria and possess- 

 ing the power of inhibiting phagocytosis of the organism producing it. 



Alexin (d\&;w, I ward off). A defensive substance having an injurious effect 

 on bacteria, and occurring in the serum of normal and immune animals. 

 It is analogous in many respects to the bacterial toxins, and, like them, 

 easily destroyed by heat, chemical agents, etc. It is probably identical 

 with complement, q.v. (For other synonyms, see p 143.) 



Amboceptor (ambo, both, and capio, I take). A specific antibody produced 

 by the injection of bacteria, red corpuscles, cells, etc., and exerting, with 

 the help of a'exin or complement, a solvent action on these substances. 

 The term is Ehrlich's, and its use should involve the acceptance of his 

 theory of its action. (For synonyms, see p. 142.) 



Anaphylaxis (d or ava, privative, and 01'Xdo-crw, I guard). The opposite of 

 prophylaxis i.e., a condition in which the susceptibility of the animal 

 (especially to toxins, serums, etc.) is abnormally increased. Practically 

 identical with hypersensitiveness. 



Antibody. A substance formed by the injection into an animal of a substance 

 (its antigen) not normally found in the juices of that animal (and probably 

 in all cases of proteid constitution, or closely allied thereto), which unites 

 with its antigen and modifies it in some way. 



Antiferment, or antienzyme. An antibody to a ferment or enzyme. 



Antigen (Avri, against, and yiyvu. I produce). A substance which, when 

 injected into a suitable animal, has the power of leading to the produc- 

 tion of an antibody. In most, if not in all, cases it is proteid in nature. 



Antitoxin. An antibody to a toxin i.e., a specific substance formed by an 

 animal in consequence of the presence in its tissues or juices of a given 

 toxin, which the antitoxin thus produced has the power of neutralizing. 



Arthus' phenomenon. A form of hypersensitiveness to serum, where in a 

 sensitized animal local lesions (gargrene, abscesses, etc.) develop in a 

 region where serum is injected, and the animal may become cachectic 

 and die. 



Atrepsy (a, privative, and rptyw, I nourish). A condition in which an infective 

 agent or collection of malignant cells dies in the animal body owing to 

 its being unable to obtain suitable nourishment : a conception intro- 

 duced by Ehrlich to explain certain forms of immunity e.g., to malignant 

 growths. 



Attenuation. The change which an organism undergoes whereby it becomes 

 less virulent. 



