GENERAL CHARACTERS AND NATURE. 183 



Most frequently occurring as an enzootic, or epizootic, it 

 may, however, though more rarely, be met with in isolated 

 instances as a sporadic disease. 



That it is contagious in the ordinary sense of the term has 

 been variously admitted and denied by different writers, whose 

 opinions are highly esteemed in such matters ; but deductions 

 derived from experiment, and the behaviour of the bacillus 

 anthracis in relation to artificially produced disease, compel 

 us to subscribe to the theory of its being communicable by the 

 alimentary tract, the air-passages, or by cutaneous inoculation, 

 and, though generally fixed, the virus may be more rarely 

 volatile. That it is transmissible is now beyond dispute, and 

 may, either fresh from the source of the poison or after a long 

 period of preservation, be conveyed by mediate objects to fresh 

 habitats and means of development. 



To the condition of receptivity of the species and individual 

 we are inclined to attach the utmost importance, and from 

 our observation we are led to look to this for much explana- 

 tion as to the apparently erratic behaviour of the anthrax 

 virus. 



We have before said the manifestations of this disease are 

 not invariably one and the same, either in species or individual. 

 But Ave feel justified, for purposes of description, in dividing 

 them into two groups, viz. : 



1. Anthrax proper as a general blood disorder, without 

 external and readily appreciable local manifestations, and 

 known to be connected with hcamal parasitism. 



2. Anthrax as a blood disease, ivith external and readily 

 appreciable inanifestations, included tuith luhich is one form 

 in ivhich the hcBTrial parasitism has not yet been so clearly de- 

 monstrated, and probably, until more definite information 

 respecting its pathology, especially cetiology, is obtained, should 

 be classed as ' Anthracoid.' 



When occurring in the first form its course is usually 

 shorter and its fatality greater than in the latter. 



It is deserving of notice, in having regard to the varied mani- 

 festations of anthrax, and the peculiarities which mark its de- 

 velopment as to the respective liability of different animals to 

 any or all of its forms, that although in Great Britain our horses 

 are comparatively exempt from attacks of anthrax, as compared 



