1 88 INFLAMMATORY AND SUPPURATIVE CONDITIONS. 



On the surface of agar and of potato the growth is an abundant moist layer 

 of the same colour. The growth on all the media has a peculiar viscid or 

 tenacious character, owing to the gelatinous character of the sheaths of the 

 cocci. 



White mice are exxeedingly susceptible to this organism. Subcutaneous 

 injection is followed by a general septicemia, the organism being found in 

 large numbers in the blood throughout the body. Guinea-pigs are less sus- 

 ceptible ; sometimes only a local abscess with a good deal of necrotic change 

 results ; sometimes there is also septicemia. 



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 sin'ce been found by other observers in some epi- 

 demics of the disease. It occurs in large numbers in the pus in the form of 

 a rounded or oval diplococcus (with the long axis lying transversely), chiefly 

 in the interior of leucocytes (Fig. 71). In fact, it closely resembles the gono- 



coccus both in morphological charac- 

 ters 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 glycerin agar and 

 Lbffler's blood serum, forming a num- 

 ber of transparent colonies which run 

 together to form a thin layer. Growth 

 occurs most rapidly at the tempera- 

 ture of the body, and entirely ceases 

 at the ordinary room temperature. 

 Individual cultures die out after two 

 to six days, but growth can be main- 

 tained indefinitely in successive sub- 

 cultures. Inoculation by ordinary 

 methods shows that it has little viru- 

 lence for guinea-pigs, rabbits, etc. 

 A number of experiments have been 

 performed 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 (p. 201). 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. 



Bacillus acnes. — According to Gilchrist this organism is the undoubted 

 cause of a pustular disease of the skin known as acne vulgaris. The morphol- 

 ogy of the organism as seen in smear preparations made direct from the pus 

 of an acne nodule, resembles very closely that of B. coli, the bacilli being 

 short and plump with rounded ends ; very rarely branching forms are met 

 with, although in old cultures such forms are not uncommon. The bacilli 



Fig. 71. — Film preparation of exudation 

 from a case of meningitis, siiowing the dipio- 

 cocci within leucocytes. 



Stained witti carbol-thionin-blue. X 1000. 



