WITH CERTAIN EXTINCT QUADRUPEDS. 377 
“Tam sorry to learn that a somewhat hasty objection has been 
made to the paleontological value of the fragment of bone which you 
exhibited. I have no right to give any opinion regarding the lo- 
cality where it was found, because I have not visited it; but the 
opinion of M. Delesse, who had an opportunity of examining all its 
geological features, is deserving of all confidence. Among the other 
fossil remains which he found in that locality, there is a fragment of 
bone of a Horse, having also traces of human agency, and which is in 
a much more altered condition than that of the bone he gave you; 
but there is another fragment ‘also bearing the mark of a saw, the 
appearance of which is quite as fresh as the specimen in your posses- 
sion ; nevertheless, when we endeavoured to authenticate this frag- 
ment specifically, we were unable to do so by comparing it with the 
homologous part in the skeleton of our living animals. 
“It is moreover important to remark that, in any given locality, 
all the bones collected do not present the same degree of organic 
change. That depends, first, on their anatomical structure being 
more or less compact according to the species, and again, chiefly 
on the composition and physical condition of the mineral matter in 
which they have been in immediate and prolonged contact. Mr. 
Hart, in his description of the Megaceros Hibernicus (Dublin, 1830), 
states that a fragment of a rib analysed by Dr. Stokes yielded 42-87 
per cent. of animal matter; and Dr. Apjohn, who analysed another 
portion of a rib, states as follows :—‘ The bone was subjected for two 
days to the action of dilute muriatic acid; and when examined at 
the end of this period, it had become as flexible as a recent bone 
submitted to the action of the same solvent. The cartilage and 
gelatine had not been perceptibly altered by time.’ It is long since 
the observation was made by many other persons, and especially by 
Schmerling (Recherches sur les ossements des cavernes de la pro- 
vince de Liége, 4to. 1833, lére, par. pp. 18-52): and the remarkable 
researches on this subject recently made by M. Delesse, and which 
he is about to publish, have demonstrated that the organic change 
in bones by no means bears a relation to their paleontological an- 
tiquity. For example, he has found that the teeth of the bone-bed 
in the Upper Keuper at Otterbronn contain more azotized organic 
matter than most of the tusks of the Mastodon and Elephant found 
in tertiary or diluvial deposits. The amount of azote which they 
yield is even almost double that in the tusks of the Mastodon in the 
VOLE, Vi. PB} MG. 
