EPIZOOTIC CELLULITIS, OE PIXK-EYE. 359 



convinced that it is highly contagious and infectious, and can 

 be conve^'ed from diseased to healthy animals with great facility. 

 Dieckerhoff says it may be readily communicated to healthy 

 horses by the intravenous or subcutaneous injection of warm 

 blood taken from a diseased animal ; and Mr. Archibald Robinson, 

 F.R.C.V.S., Greenock, says that it can be transmitted by the 

 stallion which has had the disease months before to the mare by 

 the act of coition. 



A purely infectious disease like the pleuro-pneumonia of 

 the ox follows the great lines of commerce, and can be traced 

 from place to place with a certain degree of exactitude, but a 

 miasmatic disease, which may afterwards become infectious or 

 contagious, cannot be followed from place to place. I am 

 therefore forced to the conclusion that, like Eoman and typhoid 

 fevers in man, this disease, arising as it does from the enti^ance 

 of a microbe into the animal system, is not due so much to that 

 germ itself, but to certain properties which it has obtained from 

 perhaps unknown conditions of the air ; that the germ itself is 

 constant in the surroundings of animals and under ordinary 

 conditions quite innocuous, but let those conditions be altered, 

 the properties of the germ become virulent and infectious. 



There are several examples of the so-called spontaneous 

 development of an afterwards contagious disease, — tetanus being 

 one of the most remarkable, and the same may be said of 

 anthrax, which commonly originates without any contagion, and 

 indeed, when developed in one animal, is only contagious by 

 inoculation. 



Now it appears that the infectious properties of this germ are 

 generally developed during or immediately after a long con- 

 tinuance of wet weather. Several outbreaks within my memory 

 have been so ushered, but this is not universal, as some writers 

 state that it occurs in all weathers and in all climates. This 

 might be more correctly said of the catarrhal form than of 

 the other. 



The microbes (micrococci), which I have invariably dis- 

 covered, as shown in the photo-micrographs, have a great 

 tendency to arrange themselves in pairs. (See fig. 20.) They 

 average about_ o-T-ff-ro of an inch in size, grow freely in gelatine 

 and agar-agar, and are easily stained with the aniline dyes. 

 Further observations and experiments are necessary to confirm 

 or contradict this discovery. 



