THE INFECTIOUS DISEASES. 269 



pathogenic significance in the lower animals under both natural and experimental con- 

 ditions. 



Thus the Quarter-evil (Rauschbrand ; charbon symptomatique), especially in Europe, 

 is a serious infectious disease of sheep, goats, and cattle. At the seat of infection, often 

 in the legs, there is a hsemorrhagic oedema with gas formation, the involved region often 

 becoming much swollen and black in color (" black leg "). The bacillus which is the 

 excitant of this disease is known, and preventive inoculation has been practised. 



Howard has described a group of cases of hcemoi-rhagic septiccemia characterized by 

 haemorrhages into the skin, serous membranes, and viscera, in which capsulated bacilli 

 apparently related to the above-described bacillus of Friedlander (page 189) have been 

 found. For the details of these cases and their relationship to other forms of septicaemia 

 we refer to the original paper. 1 



HYDROPHOBIA. (Babies.) 



MORPHOLOGY OF THE LESIONS. 



This is an infectious disease occurring most frequently in the carni- 

 vora, and especially common in dogs and wolves. 



The lesions are not constant nor are they characteristic. Though 

 well marked in some cases, in others they are but very slightly developed. 



FIG. 137. HYDROPHOBIA, TRANSVERSE SECTION OF SMALL BLOOD-VESSELS IN THE SPINAL CORD. 

 Showing accumulation of leucocytes and proliferation of connective-tissue cells in the adventitia of the 



Changes, when present, are apt to be most pronounced in the medulla 

 oblougata and pons, but they may be present in the spinal cord. They 

 consist of small haemorrhages, accumulation of leucocytes in the peri- 

 vascular lymph spaces about the blood-vessels (Fig. 137) and around 

 the ganglion cells, of thrombi in the smaller blood-vessels, and finally of 

 chromatolysis of the ganglion cells. 



1 Howard, Journal of Experimental Medicine, vol. iv., p. 149, 1899; see also Blumer 

 and Laird, Johns Hopkins Hospital Bull., vol. xii., 1901, p. 45. 



