162 THE ENZYME THEORY OF DISEASE [ch. xi 



was independent of the bacteria and survived when the 

 latter were killed by subjection to a temperature of 60°C. 

 Sortinin (ibid.) showed that a culture fluid after it had 

 been passed through a Chamberland filter, which removed 

 all the bacteria, still retained the power to liquefy gelatin. 

 Brunton and McFadyean (1889) found that the gelatin lique- 

 fying ferment could be isolated by suitable solvents, in the 

 same way that the inverting ferment of yeast can be extracted 

 with ether. 



11. Instances may be cited of chemical processes, taking 

 place in the body fluids, which are invariably associated with 

 the presence of certain micro-organisms but which neverthe- 

 less have been proved to be brought about by the activity 

 not of the organisms in question but of ferments associated 

 with these organisms and yet separable from them. Such an 

 instance is to be found in the action of the micrococcus ureae. 

 In the presence of this organism the urea of the urine is split 

 up with the formation of ammonium carbonate. In the 

 absence of this organism the process does not take place and 

 if the process has begun the removal of the organism at 

 once stops it. An ethereal extract, however, of the micrococcus 

 ureae has the power of accomplishing all that the presence of 

 the organism itself can effect in this direction. In other words, 

 the results brought about by its presence are due not to its 

 own activities but to those of a ferment " urase " which is in 

 some way associated with it but which can be dissociated 

 from it without any loss of function. 



12. If it were possible to discover a parallel instance of 

 dissociation, not between an organism and its chemical func- 

 tions but between an organism and its pathological functions, 

 the discovery would give great weight to the theory we are 

 discussing. Now such a parallel can actually be traced in the 

 action of the pneumococcus. Rosenow (1912-13) has recently 

 shown that the artificial injection into the body of the toxins 

 manufactured by the pneumococcus may bring about the 

 death of an animal in one of two ways. It may produce an 

 acute bronchial spasm which proves fatal in a few hours. If 

 the dose of the toxin is small the bronchial spasm may not 



