274 VETERINARY SURGICAL THERAPEUTICS. 
groups, more particularly the crural or the gluteal, as frequent com- 
plication of hemoglobinuria. Rarer are the other amyotrophies of infec- 
tious origin. Arterial thrombosis may bring on serious nutritive troubles in 
the muscles that the arteries irrigate, and when the interference with 
the flow of the blood continues and the anzmic muscular zone cannot 
recover the conditions of its normal vitality, atrophy takes hold of it. 
Ktitzner has observed in the case of a horse, with no appreciable 
cause, a progressive atrophy of the femoral biceps and of the superior 
part of the semi-tendinous—atrophy, no doubt, of embolic origin, 
which three months later brought on troubles of locomotion. Slow atrophy 
of the large gluteus has been seen by Roloff, that of the pectorals by 
Blenkinsop. Other authors have recorded analogous cases in which several 
muscular groups were affected. 
As more rare forms, some unknown, others scarcely mentioned in the 
case of animals, but frequent and well classified in the case of man, we 
may mention the myelopathic muscular, the neuropathic and the myopathic 
atrophies. 
The myelopathic amyotrophies, which are met in numerous cases of 
myelitis, have a common origin; all come from a lesion of the cells of 
the anterior horns of the spinal cord. The anatomical and clinical de- 
velopment is at times rapid (acute myelitis, hematomyela), at times slow 
(progressive muscular atrophy). Pure atrophy is the ordinary muscular 
alteration ; in some cases it is accompanied with sclerosis (sclerous atrophy). 
Sometimes atrophy is systematic, progressive and predominant (progres- 
sive muscular atrophy of Duchenne) ; in other cases, though less marked, 
it nevertheless constitutes one of the prominent phenomena of the morbid 
group (lateral amyotrophical sclerosis, syringomyelia) ; and in other cases 
it is irregular, not at all prominent, and occurs in various stages of diseases, 
of which it is but an epiphenomenon of little importance (sclerosis in 
patches). 
Neuritic muscular atrophies, which occur because of lesions of motor- 
nerves, have a more or less rapid development. Examples of them are 
common in some species, specially horses. (See Paralysis.) To that 
group to-day the amyotrophies of articular origin are added. They are 
sometimes marked by a rapidity that cannot be explained by the inertia or 
disuse of an extremity. It is admitted that they are of reflex nature, pro- 
moted by phlegmasia of the nervous branches which are distributed to the 
diseased muscles, 
Myopathic muscular atrophies seem to be independent of all spina 
or nervous alteration—at least of all visible alteration—with the present 
method of investigation. They are considered as primitive, brought on by 
pohrtic troubles localized in the muscle itself. The diseased process be- 
