ORGANISMS WHICH PRODUCE DISEASE 75 



kill off perhaps a million mice, if the poison in that amount"of 

 filtered broth-culture were diluted and inoculated into them 

 in equal amounts! Much important experimental work has 

 been performed with these toxins, at least two varieties, 

 tetanospasmin and tetanolysin, being present in the toxic 

 broth-culture. The tetanic spasms which are one of the terrible 

 accompaniments of this disease are due to the former of theso 

 toxins, which is absorbed from the area of the wound, more 

 especially along the lymphatic channels of the motor nerve- 

 sheaths passing up and attacking the motor nerve-cells of 

 the spinal cord and other parts of the central nervous system, 

 for which it has a strong chemical affinity, and so producing 

 the spasms of the corresponding muscles. 



Anti-tetanic serum, if used early, before the nervous system 

 is irreparably damaged, and in large amounts, may save the 

 patient, and should be used even as a prophylactic precaution 

 in cases of wounds the nature of which may render the patient 

 likely to develop the disease. 



B. oedematis, the bacillus of Malignant Oedema, is found 

 commonly in garden-earth and manure, often along with the 

 tetanus bacillus, the effects of both being occasionally combined 

 in the same case. It produces an intense, spreading, gangren- 

 ous cellulitis, with swelling, oedema, and gas-production, i.e. a 

 combination of necrosis and putrefaction of the tissues. It 

 may extend quickly and produce rapid death. 



The bacillus is Gram-negative, motile, and varies much in 

 length, filamentous forms being common. Large oval, more 

 or less central spores are formed. It produces gas in culture, 

 the odour being very offensive, and it liquefies gelatin. 



B. chauvaei, the cause of Quarter Evil or Blackleg in 

 cattle ; and B. welchii or B. aerpgenes capsulatus, a common 

 saprophytic gas-producing organism which occasionally becomes 

 pathogenic, but is more usually a cause of putrefaction, are 

 other members of the anaerobic group, as is also B. botulinus, 

 the cause of one form of Meat-Poisoning (see p. 41). 



The Acid-Proof Group of Bacteria and the Pathogenic 

 Trichomycetes 



The "Acid-Proof" Group of Bacteria. Certain bacilli in 

 virtue of a fatty or wax-like substance in their protoplasm or 

 cell-body, are somewhat difficult to stain, but, when they are 

 stained by certain special methods (for example, by what is 

 known as the Ziehl-Neelsen Method, where a strong dye,fuchsin, 



