PATHOGENESIS 293 



The crab is impoverished by the infection, and just barely 

 contrives to achieve a miserable form of " immunity " from 

 complete destruction by the sacrifice of its highest interests. 

 In a similar way all attempts of the body to strike up a com- 

 promise with a poison, or with a vast surplus of waste matter, 

 which amounts to the same thing, can only be carried through 

 at the expense of vitality and of evolution. The alternatives 

 are therefore either a violent or heroic effort to expel or destroy 

 the enemy, or a weak compromise by pathogenetic adaptation 

 with ultimate loss of status. What is shown on the biological 

 scale in the crab is clinically demonstrated to be true of the 

 animal or human system in a more acute form. 



7. " The anaphylactising toxin affects the central nervous 

 system, and the essential phenomenon is a disorganisation of 

 this system, with a considerable fall in the arterial blood 

 pressure." 



Again, we have thus the pathological and pathogenetic 

 effects strongly emphasised, and we are again reminded of the 

 similar potency of the vegetable alkaloids and thus gain the 

 clue to the deeper explanation of these ill-effects, viz., that 

 they consist in the biological inadequacy of the substances 

 concerned. 



But there are other less direct ill-effects of these unsuitable 

 food and other substances introduced into the blood both 

 physiological and biological. The tissues of an animal are like 

 the parts of an engine and must not be clogged or impeded by 

 interfering substances, neither must the co-ordination (a kind 

 of symbiosis) of the parts or the total energy required by this 

 co-ordination be diminished. 



In his work on Leicester : Sanitation versus Vaccination 

 (p. 693), Mr. J. T. Biggs, J.P., quotes Metchnikoff as affirm- 

 ing that " the serum of the blood of many animals will destroy 

 the red corpuscles of a different species," and Dr. Winters as 

 saying that "horse serum dissolves human blood corpuscles and 

 thereby produces new elements of decomposition." 



