126 CONTEMPORARY SCIENCE 



attitude a::d taught the distinction between the two va- 

 rieties of infectious disease and their corresponding im- 

 mune states, according as their main effects and symptoms 

 arise from the toxalbumins or poisons we have been con- 

 sidering, or ,the intimate presence within the organs of 

 the microbes themselves. The former variety chances 

 indeed to be in the minority, and hence it has come about 

 that the diseases to be successfully combated by antitoxins 

 are few in number, while those in which the microbes 

 penetrate deeply into the body and which poison its tis- 

 sues by means of so-called endotoxin, are far more num- 

 erous. The latter class includes such important diseases 

 as tuberculosis, typhoid fever, meningitis, plague, cholera, 

 the septicemias, and still others. And yet the failures 

 have been only partial, and success has been and is still 

 being won against odds which were once considered in- 

 superable. 



What is striking is the capriciousness with which the 

 microbes themselves or their endotoxins lend themselves 

 to the making of therapeutically effective serums, as con- 

 trasted with the ease and certainty of action in this re- 

 spect of the toxalbumins. All the latter seem capable of 

 yielding abundant antitoxins, and this independently of 

 their precise source, since it happens that toxalbumins re- 

 sembling those of bacterial origin exist also in the higher 

 plants as in the castor and jequirity beans and in the 

 venoms of reptiles and insects. On the other hand, it 

 has not thus far been found practicable to fashion curative 

 serums for tuberculosis, typhoid fever, plague, cholera, 

 etc., while success has been achieved in the instance of 

 epidemic meningitis, and very hopeful results have re- 

 cently been attained in the case of pneumonia. 



In meningitis the success is linked with the recognition 

 of a second principle of* action, namely the advantage to 

 be derived from what may be called the local specific 

 treatment of a disease, or the bringing of the healing 

 serum into direct and intimate relation with the seat of 



