128 WARFARE IN THE HUMAN BODY 



to more widely operating causes, or, as Mach says, in 

 showing that any given phenomenon is the unequivocal 

 function of its variables, what has to be demonstrated is 

 that those variables belong to recognized classes of factors. 

 We cannot explain life by saying that it is living, or a 

 bacteriologist by asserting that he is bacteriological. 



It is due to such habits of thought, which now appear 

 to be confirmed, that there are fewer subjects coming under 

 the heads of general physiology and biochemistry in a 

 greater state of confusion than " immunity." This result 

 may, perhaps, be due to a false belief in the profundity 

 of the Teutonic mind which, as Benjamin Moore pointed 

 out, when commenting on an original communication of 

 mine in the British Medical Journal, had seized upon 

 French work, and fogged it in its best later manner. 

 It is indeed to Weismann and Ehrlich that the 

 worst results can be directly attributed, for just as the 

 biologist explained heredity by saying that it happened 

 owing to the nature of the organism, that is, to its ids, 

 determinants, and biophors, and the like, so Ehrlich in his 

 side-chain theory invented a marvellous verbal machinery 

 of immunization, every word of which contained a " cir- 

 culus in definiendo." To the practical English worker, 

 who usually distrusts the theoretic intellect, as if a general 

 idea were a proof of original sin unless it comes to him from 

 abroad, this scheme was a godsend. It appeared to save 

 thought, and instead of examining it critically he has 

 patched it up with new words as they seemed to be wanted, 

 just as the Ptolemaic astronomy added eccentric to 

 eccentric and epicycle to epicycle in order to represent 

 the planetary motions. And yet the whole theory is 

 obviously false. To this every modern physiologist would 

 subscribe, seeing that it depends for its validity on the 



