20 Williams, Fisher, and Udall: The Spavin Group. 
excreted in the urine of the horse while others are insistent that 
it is so excreted in measureable quantity. It would appear that 
one of the great difficulties in the analysis of the urine of the 
horse is an attempt to apply the methods used in examining the 
urine of man, especially quick, approximate methods which yield 
reasonably accurate results, or rather estimates in human urine, 
and which may be in part or wholly invalidated by the widely - 
dissimilar character of equine urine. Have the different. investi- 
gators dealt with urine of essentially different composition? Was 
that urine which contained phosphates normal? In the fore- 
going we find in acute ringbone a maximum of 4.55 grammes of 
phosphoric acid (P205) equivalent to 10.18 grammes of calcium 
phosphate (Ca3(-PO4)2) and then meet with complete negation 
in normal work animals. 
Another interesting feature is the effect of the feeding of 
large quantities of phosphates upon their excretion by the kid- 
neys. After the animals from which samples 2,673 and 2,674 
were taken had later been given two to three ounces daily of 
sodium phosphate in their food, the former showed .og grammes 
of P205 per liter of urine or .02 of the quantity observed in 
2,676, while the later, 2,674, showed only traces of phosphates. 
This would appear to suggest that the ingestion of an unusual 
amount of phosphates tends to establish or increase their presence _ 
in the urine, but only very slightly as related to the amount in- 
gested, most of it evidently being excreted by the intestinal tract’: 
or other avenues of egress. 
Urinalysis appears to be a most inviting field for the further 
study of this malady. 
ETIOLOGY. 
As most authors consider the entire group to be so many 
distinct affections, they attempt to elucidate separate causes in 
each instance, and in so doing have invoked for each, almost 
every conceivable form of mechanical insult and other injuries. 
Confessing the identity of the lesions, wherever they may | 
occur, we should admit a cosmopolitan reason for their existence, _ 
which would serve equally to explain spavin, navicular disease, ° 
fracture of the ribs, anchylosis of the vertebrz, or any other 
member of the group. As an illustration we might take the 
horse .from which Figures XVII and XVIII are taken. Here 
