FISSION FUNGI AS CAUSES OF DISEASE. 639 



by the action of the products, is very characteristically 

 seen in the progressive necrosis of tissue observed by 

 Koch in the case of mice (see p. 209), also in connec- 

 tion with the bacilli of pigeon diphtheria, &c. (see 

 p. 326). It is probable that such bacteria do not 

 always lead to a progressive destruction of the tissue ; at 

 times it is evident that such a violent reaction and such 

 a great new formation of cells occurs that the develop- 

 ment of the bacteria and the production of the injurious 

 materials cannot keep pace with it; in that case the 

 inflammation indicates the limit and the end of the 

 bacterial development. 



Another mode of development within the living body Development 

 is illustrated for example by the bacilli of malignant parasites. 10 

 oedema, and of symptomatic anthrax. These bacilli, 

 belonging to the class of anaerobes, are not able to 

 multiply in the living blood, nor in open wounds, nor 

 can they grow when introduced in minute quantities ; 

 on the contrary, they require the previous occurrence of 

 an injury which must furnish at least a certain amount 

 of dead tissue, and further they must be present in large 

 numbers from the beginning; or if a wound is present 

 oxygen must to a certain extent be excluded from it ; 

 further, the bacilli do not penetrate in all directions in 

 the various tissues of the body, they only grow where 

 the smallest amount of interchange of gases renders 

 their existence easier, for example in the subcuta- 

 neous cellular tissue, or in the serous coverings of 

 the organs ; and it is only when the whole body 

 has become extremely poor in oxygen as a rule only 

 after death that they are able to develop in the blood 

 and in the various internal organs. 



Another mode of spread and penetration is shown by Penetration 

 the micrococci of erysipelas. These also do not multiply lymphatic 

 in the blood-vessels, nor, when injected into the veins, vessels - 

 do they cause any disease of internal organs ; on the 

 contrary, they only grow in the lymph channels of the 

 skin, exciting here a locally limited inflammation, and 

 furnishing also, in all probability, toxic materials, by 

 the absorption of which the marked general symptoms 



