IMMUNITY 411 



» 

 specially worked out by Sidney Martin. He separated from the 

 tissues, and especially from the spleen, of patients who have 

 died from diphtheria, by precipitation with alcohol, chemical 

 substances of two kinds, namely, albumoses (proto- and deutero-, 

 but especially the latter), and an organic acid. The albumoses, 

 when injected into rabbits, especially in repeated doses, produce 

 fever, diarrhoea, paresis, and loss of weight, with ultimately a 

 fatal result. He further found that the paresis is due to 

 well-marked changes in the nerves. Substances obtained from 

 diphtheria membrane have an action like that of the bodies 

 obtained from the spleen, but in higher degree. Martin con- 

 sidered that this is due to the presence in the membrane of an 

 enzyme which has a proteolytic action within the body, resulting 

 in the formation of poisonous albumoses. 



Immunity. — This is described in the general chapter on 

 Immunity. It is sufficient to state here that a high degree of 

 immunity, against both the bacilli and their toxins, can be 

 produced in various animals by gradually increasing doses either 

 of the bacilli or of, their filtered toxins (vide Chapter XXII.). As 

 a result of the immunisation, antitoxins appear in the serum, 

 and these are capable of protecting animals against infection 

 either with diphtheria bacilli or their toxins. They also have 

 curative effects in animals which are already the subjects either 

 of infection or intoxication. 



Therapeutic Effects of Diphtheria Antitoxin. — The use of this 

 antitoxin for the prevention and treatment of diphtheria con- 

 stituted the first great contribution of bacteriology to practical 

 therapeutics. For the protection of an individual exposed to 

 infection 500 units of antitoxin are administered by the sub- 

 cutaneous route, and in a case of the established disease from 

 2000 to 4000 units, according to the severity of the symptoms. 

 By the application of the method a very great diminution in the 

 mortality has resulted. The diphtheria antitoxin came into 

 general use about October 1894, and the statistics published by 

 Behring towards the end of 1895 indicated results which have 

 since been confirmed. In the Berlin Hospitals the average 

 mortality for the years 1891-93 was 36-1 per cent., in 1894 it 

 was 21-1 per cent, and in January- July 1895, 14-9 per cent. 

 The objection that in some epidemics a very mild type of disease 

 prevails is met by the fact that similar diminutions of mortality 

 have occurred all over the world. Loddo collected the results 

 of 7000 cases in Europe, America, Australia, and Japan, in 

 which the mortality was 20 per cent, as compared with a former 

 mortality in the same hospitals of 44 per cent. When the treat- 



