512 
Rickets, Bone Softening, and Paralysis 
other adverse conditions of a climatic nature are in existence 
at this time, many of the helpless lambs will become attacked 
with arthritic, i.e. joint, disease, — the disposition to rest on 
the cold ground, together with defective alimentation, operating 
as immediately inducing factors in the production of joint- 
disturbance. 
As regards older animals — sheep of the first year, which . 
become affected with this weakness of the back — they are 
chiefly those which have from their infancy been reared, for 
intervals at least, on the situations subject to it, or whose 
dams, during pregnancy, have been similarly treated. The 
disposing influences have not in their case been powerful 
enough to determine its appearance when lambs ; but being to 
some extent continued, will still, as hoggets, claim a certain 
number of victims ; while if attempts are made to fold them on 
turnips on the lands indicated during the first winter, without 
due attention to allowing some additional food-materials, a 
considerable loss may be anticipated. The impairment of 
motorial power in these instances will most surely be developed 
should the state of the weather be such that the land on which 
they are folded becomes saturated with water, so as to render 
travelling over it attended with difficulty. 
2. — Bone-softening, "Mollites ossium." 
Definition. — A condition in which the bones of the skeleton,, 
chiefly in young sheep, gradually become decalcified, rendering 
them unfit to serve the purpose of passive organs of locomotion, 
and liable to be fractured from trivial causes. 
Nature and General Characters of the Condition. — This, like 
the preceding affection, is peculiarly a disease of particular 
localities, being only met with on certain soils, and on these 
when interfered with as previously described. The impairment 
of nutrition is here confined to, or only exhibited in its purity 
in, the bones of the extremities. It is less liable to affect the 
very young than such as have reached, or nearly reached, 
maturity. The essential materials of which bone is formed do 
not seem to be wanting at the exact period of their formation ; 
but having been elaborated, and their growth so far completed, 
certain portions are more rapidly removed, or on removal in the 
process of growth, are not replaced. The inorganic or earthy 
portions seem to be replaced by excess of the softer organic 
constituents. 
Although I am disposed to regard this affection as a general 
disease affecting the nutrition of this particular tissue — i.e bone 
— it may, and has, I believe, been regarded in another light. 
