437 
of Running Water on Skeletons. 
average ; the small volume of water at work would thus be to 
some extent compensated. 
III. The foregoing notes present the chief points of interest 
in connection with the subject in question. Two further remarks 
appear appropriate with regard to the bones themselves. 
In the first place, the bones shew that the shoulder-joint of 
the pony “ A” was in an advanced stage of the disease called 
Osteo-arthritis. Such an advanced stage of this condition is rare, 
though not unknown, in the horse. The. subject derives a special 
interest from the point of view of the relation of disease to diet, 
whether in Man or the horse. A purely vegetable diet would not 
seem to be an efficient safeguard against the onset of Osteo- 
arthritis. This subject has been ably discussed by Dr Balfour 
in the Edinburgh Medical Journal (Feb. 1870, p. 713), where 
special reference to Osteo-arthritis in the horse is made. Again, 
Virchow ( loc . cit. Z. fur Ethnologie) describes a not dissimilar 
condition in bones of the extinct cave-bear ( Ursus spelaeus) under 
the name of Hohlen-gicht. Evidence of similar conditions in 
early Tertiary ungulates was given by Professor Marsh at the 
International Congress of Zoologists at Leyden in 1895. Secondly 
and lastly, the water of this particular stream and marsh seems 
to have contained sufficient acid (whether vegetable or other) to 
lead to disintegration of the bones in certain places. This effect 
must be very carefully distinguished from those of Osteo-arthritis. 
In the latter, the joint-surfaces and the neighbouring parts 
of the bones will be affected, and in such a way that erosion and 
eburnation (polishing) of the joint-surface is found accompanied 
by bony outgrowths around the margins of the latter. Erosion 
due to acidity of the water first affects the very thinnest parts 
of the bones and is accompanied of course by nothing in the way 
of exostosis. The scapula of “A” shews both conditions very 
excellently, the joint region affording evidence of Osteo-arthritis 
as already said, and the blade of the scapula being perforated 
in its thimiest part by the solvent action of the water. 
