40 BACTERIOLOGY. 



Bacterio- tissues to form substances, circulating in the blood- 

 serum, which combine with and neutralize the poisons 

 of bacteria. They are spoken of as antibodies and act 

 in different ways; some, called bacteriolysins, dis- 



"tSfn U s~ s l ve tne bacterial cells ; others gather the bacteria into 

 clumps or clusters; these are called agglutinins; and 

 finally substances may be formed that act on the bac- 

 teria in such a way as toi make them more readily 



opsonins digested by the phagocytes; these are called opsonins. 



It is an interesting fact, and one of; much impor- 

 tance, that the amount of these protective substances 

 formed is not only sufficient to 1 render an infection 

 harmless, but is greatly in excess of the needs of the 

 moment. They remain stored away in the tissues 

 ready to be utilized when the same infective agent 

 again attacks; this is the way that immunity is 

 established. 



The word anaphylaxis, literally translated from 

 the Greek, means against protection, the exact op- 

 posite of prophylaxis, which means for protection. 

 This name has been given to a condition of hypersen- 

 sitiveness which has been found to exist in certain 

 animals and man. For example, it has been shown 

 that guinea-pigs may be made sensitive to harmless 

 proteids like egg-albumin or milk. The first injec- 

 tion causes no symptoms, but the second, even when 

 the dose is smaller, may cause shortness of breath, 

 spasms, and death. It requires from: ten to fourteen 

 days after the first injection for this hypersensitiveness 

 to develop. 



