660 DR JAMES W. DAWSON ON 



many remissions, the "noxa" responsible must remain constant in the body, lead 

 at certain periods to relapse, or even remain latent for a long period. The assump- 

 tion of an auto-toxin agrees with this demand, and the example of pernicious 

 anaemia in which the remissions may probably be traced to the result of absorption 

 into the portal tract of some poisonous substances may serve as a possible analogy. 

 The assumption of an organismal stimulus moving about in the body or malignantly 

 stored in depots such as the spleen or bone-marrow, or of the elaboration products 

 of such organisms continually reforming and leading to new symptoms, would also 

 agree with this demand. It is impossible to say that this is improbable, for the 

 relapses in malaria and relapsing fever coincide with the reappearance in the 

 circulating blood of free sporocytes of the malarial organism or of the spirillum of 

 Obermeyer, respectively : such relapse is therefore a re-infection from within 

 (Ainley Walker). In para-syphilis, also, it must be supposed that the specific 

 organism in some form enters the central nervous system, remaining latent for 

 years either in the lymph vessels or in the brain tissues proper, and exerting its 

 effect either by its direct action or by its toxins. The influence of such factors as 

 infectious diseases, cold, trauma, etc., would thus be to produce an impairment 

 of the nervous tissues, and so predispose them to degeneration from auto-toxins 

 and other causes : or the lowered body resistance would allow of sufficient con- 

 centration of the toxin, through deficient elimination : or a combination of both 

 factors, impairment of the tissues and an increasing intensity of the " noxa," 

 probably acts in varying degrees in every case. 



The views that have been put forward as to the source of the possible " auto- 

 toxin " can be only briefly touched upon. McCormac suggests that disseminated 

 sclerosis is due to physico-chemical causes, which may be in operation for a long 

 time, and thinks that as indol, skatol, and phenol — toxic products of intestinal putre- 

 faction — might produce structural changes in the liver which are followed by 

 nervous symptoms, it is possible that actual structural changes might occur in the 

 nervous system itself. Bramwell suggests several possibilities : the toxic agent 

 may be the result of deranged metabolism, possibly in the liver or some other 

 organ, or it may be generated in and absorbed from the gastro-intestinal tract, as 

 is probable in pernicious anaemia. The effect of exposure to cold in the production 

 of haemoglobinuria is explained by the probable rapid production of some toxic 

 substance, the result of deranged metabolism. It is thought that the exposure to 

 cold acts reflexly through the nervous system on some central organ — perhaps the 

 liver — and produces a poison which is the cause of the rapid destruction of red 

 blood cells, and that disseminated sclerosis might be the result of a chemical 

 poison similarly formed. Another possibility is that the agent may not be a 

 toxin properly so-called, but that the composition of the blood is so altered that 

 some substance or substances necessary for the nutrition of the nervous tissues, 

 especially the nerve fibres, is absent, or that the blood contains some substance 



