Immunity acquired by natural means 435 



malarial regions. Glogner in support of his view cites the case of the 

 children of the orphanage at Samarang (Java), who for many years 

 are subject to relapses and to malarial re-infections and are incapable 

 of acquiring the slightest immunity. According to Koch, Glogner's 

 example cannot be compared with that of the children of New Guinea. 

 In the former case, the natural course of the disease is interrupted by 

 treatment with quinine, which must prevent immunity being set up ; 

 whilst, in the latter, the children are abandoned to their fate, and, 

 receiving no treatment, slowly acquire a true immunity. It is 

 evident that this acquired immunity in malaria is a complex pheno- 

 menon on which fresh researches must be made ; but it cannot be 

 questioned that, under certain conditions, it comes under the general 

 rule and can be naturally acquired. 



This general rule is that, in infective diseases, immunity is 

 usually developed after a first attack. The acquired refractory 

 condition is of very long duration in certain cases, but very 

 transitory in others. To the discovery of the vaccination by at- 

 tenuated micro-organisms, made by Pasteur and his collaborators, 

 the objection was often made that many diseases, such as anthrax, 

 might relapse. This is undoubtedly the case; the anthrax bacillus 

 may attack the same individual several times; nevertheless the 

 acquired immunity against this disease is very real, though the 

 refractory condition lasts for one or a few years only, instead of 

 persisting for a very much longer period, as in the case of typhoid 

 fever, mumps, and small-pox. Bearing in mind the possibility of a 

 relapse in the case of these infective maladies, attempts at artificial 

 vaccination should never be relinquished. 



Among the examples of immunity acquired by natural means 

 must be cited that of syphilis, a very special case. It has long been 

 known and demonstrated by numerous experiments on man, that 

 individuals who have presented the primary symptoms of syphilis 

 contract a marked immunity against a new infection. The syphilitic 

 chancre does not relapse, and yet this very manifest and persistent 

 immunity does not prevent the individual, immune against re-infec- 

 tion, from continuing to be ill and of being the field for the later 

 syphilitic phenomena. This special refractory condition has done 

 great service in establishing the etiology of certain diseases which we [457] 

 were justified in suspecting to be of syphilitic origin. Many clinical 

 observers have accepted this origin for general progressive paralysis. 

 Others deny any causal relation between the two diseases. Krafft- 



i'S 2 



