32 Williams, Fisher, and Udall: The Spavin Group. 
warranted at present in arriving at the conclusion that rheu- 
matism plays any important part etiologically. 
Conractous Pneumonia (Brustseuche). Dieckerhoff has 
observed the frequent occurrence of spavin following conva- 
lescence after contagious pneumonia. This is a common obser- 
vation and applies quite as fully to other members of the group. 
As already related, the horse from which Figs. XVII, XVIII, 
VIII, and IX were taken, after having apparently become 
convalescent from contagious pneumonia, quickly developed 
tendonitis and tendo-vaginitis, on which account he was des- 
troyed, when beneath these swellings were found ringbone, side- 
bones, navicular disease, and sesamoiditis, and, upon opening 
the chest, thirteen fractured ribs and anchylosis of the vertebrz 
were revealed. Probably other contagious fevers of the horse 
tend to usher in this group of lamenesses, and certainly we know 
that any injury which may confine a horse in the stable for a 
long period, especially if the general system is markedly de- 
pressed, is very liable to finally end in an attack of this malady. 
So far as we know, the contagious pneumonia or other 
affection has no immediate relation or, rather, it does not con- 
stitute an expression of the former, but by its debilitating influ- 
ence prepares the way for spavin and its allies. 
RHACHITIS, OSTEO-POROSIS, OSTEO-MALACIE. In the affection 
or affections variously described as osteo-porosis, osteo-malacie, 
and rickets, we meet frequently with spavins, ringbones, gonitis, 
etc., which are not distinguishable during life from the ordinary 
affection ascribed to other causes. In our paper presented to this 
association (“ Rhachitis.” Proceedings of U.S.V.M.A., 18g1, 
page 113), we cited cases in which enormous spavins developed 
during a well-marked attack of osteo-porosis, that in the same 
stable nearly all weanlings died from typical rhachitis, some 
of them suffering from spontaneous fracture of the spinal col- 
umn, while some older colts suffered from lordosis, kyphosis, 
or skoliosis. When spavin and its allies occur during rickets, 
osteo-porosis, or osteo-malacie, it appears to be an essential part 
of the malady itself, not a result of it. Our knowledge of the 
relationship existing between osteo-malacie, osteo-porosis, and 
thachitis has not been determined; some believe they are iden- 
tical, others consider them different, but fail to fix the boundaries 
between them or establish definite rules for differentiation. 
Prominent members of this society have time and again urged 
