SF.PTIC BLOOD DISEASES. 397 



signs of putrid intoxication, arising from the absorption of the 

 microbes or of the cadaveric ptomaine. 



These observations only apply to the putrefaction of vegetable 

 materials when occurring in ponds or ditches exposed to air 

 and sunlight, for if the same materials are retained in leaky 

 liquid manure tanks, and thus contaminate pump wells or other 

 source of the supply of drinking waters, their effects are quite 

 as disastrous as those emanating from animal sources. It is 

 difficult to explain this fact, unless it be admitted that the 

 algte and other vegetations of low origin, which grow abundantly 

 in ponds exposed to sunshine and air, either destroy the septic 

 microbes or produce an anti-ptomaine, which overcomes the 

 virulence by breaking down the toxic materials into simpler 

 forms — ammonia, &c. 



It is difficult to conceive a general septicremia without the 

 actual presence of the microbes in the circulation, and un- 

 doubtedly, in many of the most fatal forms, the organisms are 

 existent in the blood. As a rule, however, the blood does not 

 seem to be a suitable medium for their development and growth ; 

 they soon disappear from it, being anaerobic, are destroyed by the 

 oxygen, or are arrested in the capillaries of the liver, spleen, 

 kidneys, &c., and are there quickly destroyed ; their virulence 

 is thus overcome, and the disease is not transmitted from one 

 animal to another. 



In many cases, however, the germs remain external to the 

 tissues, and act solely through their products, which gain 

 entrance into the circulation and produce their virulent effects 

 — sepsine poisoning. 



In many instances septic microbes or their products gain 

 entrance into the body from without — traumatic septicaemia, 

 septic metritis, &c. ; but there are other instances where they are 

 formed within the body itself, and microbes, always existent in 

 the intestines, may give rise to systemic and local disturbances 

 of a grave or even fatal nature. 



The intestinal mucous membrane — always in contact with 

 decomposing materials — has the power, whilst in health, of 

 excluding them from entrance into the circulation ; but when 

 that membrane is irritated in any way and by any cause, it not 

 infrequently loses that power of exclusion, and the ptomaines, 

 iudol^ skatol, gaseous products, &c., instead of being eliminated, 



