DISTURBANCES OF METABOLISM, ETC. 185 



many of ther diseases the causal organism has not yet been 

 isolated. \\ e have, however, the important fact that corre- 

 sponding skin eruptions may be produced by poisoning with 

 certain drugs. In the nervous system degenerative changes 

 have been found in diphtheria, both in the spinal cord and in 

 the peripheral nerves, and have been reproduced experimentally 

 by the products of the diphtheria bacilli. There is also experi- 

 mental evidence that the bacillus coli communis and the strepto- 

 coccus pyogenes may, by means of their products, produce areas 

 of softening in the spinal cord, and this may furnish an ex- 

 planation of some of the lesions found clinically. It is also 

 p -ilile that some serous inflammations may be produced in the 

 same way. 



B. Disturbances of Metabolism, etc. It will easily be 

 realised that such profound tissue changes as have been detailed 

 cannot occur without great interference with the normal bodily 

 metabolism. General malnutrition and cachexia are of common 

 occurrence, and it is a striking fact found by experiment that 

 alter injection of bacterial products, e.g. of the diphtheria 

 bacillus, a marked loss of body weight often occurs which may 

 be progressive, leading to the death of the animal. In bacterial 

 disease assimilation is often imperfect, for the digestive glands 

 are affected, it may be, by actual poisoning by bacterial products, it 

 may be by the occurrence of fever, and excretion is interfered with 

 by the damage done to the excretory cells. But of all the changes 

 in metabolism the most difficult to understand is the occurrence 

 of that interference with the heat-regulating mechanism which 

 results in fever. The degree and course of the latter vary, 

 sometimes conforming to a more or less definite type, where the 

 bacilli are selective in their field of operation, as in croupous 

 pneumonia or typhoid, sometimes being of a very irregular kind, 

 especially when the bacteria from time to time invade fresh 

 areas of the body, as in pyaemic affections. The main point of 

 interest regarding the development of fever is as to whether it is 

 a direct effect of the circulation of bacterial toxins, or if it is to 

 be looked on as part of the reaction of the body against the 

 irritant. This question has still to be settled, and all that we 

 can do is to adduce certain facts bearing on it. Thus in diph- 

 theiia and tetanus, where toxic action leading to degeneration 

 plays such an important part, fever may be a very subsidiary 

 feature, except in the terminal stage of the latter disease ; and 

 in fact in diphtheria profoundly toxic effects may be produced 

 with little or no interference with heat regulation. On the 

 other hand, in bacterial disease, where defensive and reparative 



