1713 BACTERIOLOGY. 



CHAPTEE XXIX. 



IMMUNITY, TOXINS, ETC. GERMICIDES, ANTISEPTICS, ETC. 



Ptomaines. This term applies to all compounds of a basic na- 

 ture produced by the agency of bacteria, They act upon the sys- 

 tem to produce the symptoms of the diseases ascribed to the species 

 through whose agency they are manufactured. 



Toxalbumins. These are proteid poisons produced by bacteria, 

 and they give rise to the symptoms of the larger number of infec- 

 tious diseases. 



Leucomaines have been defined as " basic substances which re- 

 sult from tissue metabolism in the body/' 



Toxins, This is a general term applied to all poisons produced 

 by bacteria, and especially to those of unknown composition. 



Antitoxins. Bacteria also produce another class of compounds 

 known as antitoxins. These act upon the tissues in such a way 

 as to prevent bacterial infection. 



Immunity. This term is applied to the power of resistance to 

 bacterial infection which may be exerted by an individual man or 

 animal. This may be natural ; or it may be acquired by disease, ac- 

 climatization, vaccination, the injection of antitoxins, and other 

 means. 



An antiseptic is a substance which simply retards the growth of 

 bacteria. 



A germicide is a substance which will kill bacteria, The term 

 " disinfectant" has the same significance. Among the commonly used 

 and most effective germicides may be named the following: Car- 

 bolic acid, mercuric chloride, silver nitrate, formaldehyde, sulphur 

 dioxid, calcium hypochlorite, lime, potassium permanganate, and 

 copper sulphate. 



For the destruction of the sputum of consumptives and the 

 evacuations of cholera and typhoid patients, Crookshank recom- 

 mends the use of carbolic acid, one in twenty, or a strong solution 

 of chloride of lime. Disinfection of the skin is often difficult, as a 

 number of species are of frequent occurrence upon its surface, such 



