OSTEOPOROSIS. 
29 
hair-splitting in separating this diseased condition from those 
other similar, and to my mind, identical diseases, osteomalacia 
and rachitis. I am of the opinion that it would be much 
nearer accurate nomenclature, to use the term rachitis to 
cover all the other forms constituting the so-called diseases, 
osteoporosis, osteomalacia, rickets, etc. The most of the lit¬ 
erature upon this subject we find in works upon human path- 
ology, and this is unfortunate from the fact that the human 
subject does not offer the field for careful pathological study 
that is offered when the subjects are from some of the lower 
orders. A multiplicity of names tends to confuse, and it 
seems to me that the writings of most of our authors are con¬ 
fused by this very cause. I think that we are warranted in 
assuming that the rickets of the dog or pig, and the osteo¬ 
porosis of the horse are nearly enough alike in their path¬ 
ology and etiology to be generically, at least, classed together, 
under the term rachitis. Prof. W. L. Williams, in a discus¬ 
sion of this subject, in a paper read by him before the U. S. 
V. M. A., held in Washington, in September, 1891, discussed 
this subject in a masterly manner, and 1 can do no better than 
to commend his paper to your careful consideration. 
Among the writers upon human medicine it seems to be 
pretty well agreed that rickets is a persistence of the soft 
condition of the bones of the young animal, owing to a failure 
in the process of calcification, while osteomalacia is more a 
condition of age, and results in a re-softening of the bones by 
a process of decalcification. Among the various descriptions 
of osteoporosis, we find one writer describing a condition 
which has been described by some one else under the term 
rickets, and another describes as the same disease those 
symptoms which by some one else are described as osteo¬ 
malacia. We must have something else than age upon which 
to base a classification. The pathological conditions noted in 
this disease, do not, as it seems to me, give sufficient grounds 
upon which to differentiate. Bilroth, in his “ Surgical 
Pathology,” in writing of predisposing causes of fractures, 
writes of rickets, “ which is due to deficient deposit of lime 
salts in the bone.” Again of rachitis and osteomalacia, he 
