CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 253 



ing' of the infections principle by continnons cold weather, or by a lieavy 

 frost, and the wholesale infection of Northern herds of cattle — will find 

 a full explanation, if the slaver constitutes the medium, in which the 

 patho|jenic principle lives and propagates in the Southern cattle when 

 taken north, and in which it is deposited ou the grass, in the water, 

 &c., while the same cannot be explained, if not the saliva, or rather the 

 saliva and mucous secretion combined, but something else constitutes 

 the medium. 



As above stated, I have reasons to believe that of those bacteria 

 found in the morbidly affected parts, particularly in the liver and in 

 the sj)leen of cattle affected with the southern fever, the bacilli and 

 not the micrococci constitute the pathogenic principle, or bear a casual 

 connection to the morbid i)rocess. Still, I will not deny that the mi- 

 crococci, too, may possibly possess septic properties, particularly if ob- 

 tained from a part in a slate of dissolution, for instance, from the 

 spleen, an organ which 1 invariably, at every postmortem examination, 

 found to be in a disorganized couditiou, eveu if the affected animal has 

 been killed by bleeding or by a i)istol-ball. Such micrococci, if inocu- 

 lated into the organism of a healthy aninuil, may have a septic effect, 

 and may even cause disease and death, and still may not constitute the 

 infectious principle of the southern fever. According to what is known 

 of the behavior and the pathogenic action of the various known path- 

 ogenic bacteria the morbid process and the morbid changes ih southern 

 cattle fever point toward bacilli and not at all toward micrococci as the 

 probable cause. Particularly the fact that the infectious princii)le, 

 whatever it may be, is never conveyed through the air from one place 

 to another, and requires in order to produce morbid changes in an ani- 

 mal a very long jjcriod of incubation, and then rather suddenly de- 

 velops its malignant action, it seems to me almost excludes the possi- 

 bility of a micrococcus constituting- the cause. It is true, in anthrax, 

 a, disease known to be caused by a bacillus, the period of incubation is 

 a very short one, at least in those cases in which the disease is com- 

 municated from a diseased to a healthy animal, but the attack invaria- 

 bly is a sudden one, and Bacillus unthracis not only shows a very 

 rapid propagation, but is also otherwise entirely different froiu the ba- 

 cilli found in southern cattle fever. A micrococcus, as a rule, propa- 

 gates too rapidly to require a very long lime for the development of its 

 pathogenic action, and would fill the wliole organism, aiul very likely 

 be found in every dro}) of blood, long before the sometimes vciy long- 

 periods of incubation of the southern fever has expired ; besides that, 

 every infectious principle known to consist of micrococci or dii)loci)Cci 

 is more or less volatile and can be communicated tlirougli the air, while 

 those consisting of bacilli usually' show a different behavior. But of 

 course, if there were no other reasons, those just given, resting only 

 upon analogy, might not carry much weight, or decide anything, and 

 might be met by saying that the micrococci or diplococci found in 



