172 SUPPURATION AND ALLIED CONDITIONS. 



viscid or tenacious character, owing to the gelatinous character of the 

 sheaths of the cocci. 



White mice are exceedingly susceptible to this organism. Sub- 

 cutaneous injection is followed by a general septicaemia, the organism 

 being found in large numbers in the blood throughout the body. 

 Guinea-pigs are less susceptible ; sometimes only a local abscess with 

 a good deal of necrotic change results, sometimes there is also 

 septicaemia. 



Diplococcus Intracellularis Meningitidis. This organism was first 

 found by Weichselbaum in the purulent exudate in a number of cases 

 of cerebro-spinal meningitis, and has since been found by other 

 observers in some epidemics of the disease. In the recorded cases 

 it has been described as occurring in large numbers in the pus in the 

 form of a rounded or oval diplococcus (with the long axis lying trans- 

 versely), chiefly in the interior of leucocytes. In fact, it closely 

 resembles the gonococcus both in morphological characters and in 

 arrangement. Like the latter also it loses the stain in Gram's method. 

 Its conditions of growth outside the body are somewhat limited. It 

 grows best on agar and glycerine agar, forming a number of transparent 

 colonies which run together to form a thin layer. Growth occurs most 

 rapidly at the temperature of the body, and entirely ceases at the 

 ordinary room temperature. Individual cultures die out after six days, 

 but growth can be maintained indefinitely in successive sub-cultures. 

 Inoculation by ordinary methods shows that it has little virulence for 

 guinea-pigs, rabbits, etc. A number of experiments have been per- 

 formed by introducing pure cultures under the dura, and in some cases 

 meningitis and encephalitis have resulted, but the disease as it affects 

 the human subject is not fully reproduced. From the constancy with 

 which it has been found in the various cases of some epidemics there can 

 be little doubt that it is the causal agent in a certain proportion of 

 cases of cerebro-spinal meningitis. It is of interest to note that in a 

 considerable number of such cases it has been detected during the 

 disease in the nasal secretion, whereas in normal individuals it is very 

 rare. 



Experimental Inoculation; We shall consider chiefly 

 the staphylococcus pyogenes aureus and the streptococcus 

 pyogenes, as these have been most fully studied. 



It may be stated at the outset that the occurrence of 

 suppuration depends upon the number of organisms intro- 

 duced into the tissues, the number necessary varying not 

 only in different animals (e.g., suppuration being much more 

 easily produced in rabbits than in dogs) but also in different 

 parts of the same animal, a smaller number producing 

 suppuration in the anterior chamber of the eye, for example, 



