390 
OBSERVATIONS ON THE AGE OF THE OX. 
may, without danger of erring greatly, lay down the ages of such 
animals according to the following rules : — 
From eighteen months to two years, the front temporary incisors 
are shed and replaced by the permanent incisors. 
From two years and a half to three years, the middle temporary 
incisors are shed and replaced by the middle permanent teeth. 
From three years and a half to four years, the second middle 
temporary incisors are shed, and are replaced by the second middle 
permanent incisor teeth. 
From four years and a half to five, the corner temporary are 
shed and replaced by the corner permanent teeth. 
Such are, in fact, the rules laid down in veterinary works 
especially devoted to the subject, and by which the most dis- 
tinguished men of our profession are guided, of which it is easy to 
be convinced by casting one’s eyes over the works on the age of 
oxen, published by MM. Girard (father), Huzard (son), Cruzel, 
Bernard, and, more recently, Professor Lecoq. 
But these rules, the result of long and accurate observation, and 
correct and well founded at the time when and in the countries 
where they were made, are no longer applicable and true in regard 
to certain individuals and certain breeds. 
Indeed, thanks to the progress of agriculture, to a better system 
of management and feeding of cattle, and to judicious and ad- 
vantageous crossings, it is certain that, for some years past, many 
of our bovine races have experienced in their form, and especially 
in their precocity of development, remarkable ameliorations. Culled 
provender, given unsparingly at an early age, on the one part, and, 
on the other, a happy choice of the finest (breeding) stock, either out 
of the same breed or from strange breeds, have led to such happy 
results. 
Whatever may be the causes of this remarkable aptitude in 
certain breeds to acquire their growth early, it is readily conceiv- 
able that such precocious development cannot be confined to any 
particular organs. If every part has not equally participated in it, 
at least they are all affected more or less by it. Above all, the 
digestive system — the part called on to play an important part in 
the preparation of such aptitude, since all must essentially result 
from the nature and action of alimentation — the digestive system, 
I say, must be one of the first to undergo important modifications : 
it ought to be the first to acquire the maximum of activity and 
power, in order that it might act with increased energy and effect 
on the solid and substantial aliments on which animals feed, not 
only in greater abundance, but at an age at which Nature never in- 
tended them to be so highly fed. 
Physiologically, therefore, it may be argued, we must admit that 
