OSTEO-POROSIS. 193 



latterly appeared in thorough-bred stock in Australia, where 

 it is erroneously ascribed by some to forcing the growth of the 

 young by over-feeding. 



Osteo-porosis is not confined to the horse and sheep ; cattle 

 reared on bad ill-drained land, poorly kept in the winter, grazed 

 on sterUe upland pastures during dry summers, oi otherwise ill- 

 used, being liable to be affected with it. They present symptoms 

 of rheumatic lameness, terminatiag in spontaneous fracture of 

 the bones involved. 



The disease in sheep, as explained by the following history, 

 kindly supplied by Mr. Eobertson of Kelso, is not uncommon. 



" Sheep of all breeds and of every age are, under certain con- 

 ditions of son and cultivation, externally liable to a peculiar 

 form of non-inflammatory disease of bone, more nearly resem- 

 bling osteo-porosis, as here described, than aught else I am 

 aware of. 



" Every appearance of this disease with which I am acquainted 

 has been in stock pastured on what is known as weak moor- 

 land, recently reclaimed and limed, or fed with roots grown on 

 sell of this character undergoing reclamation. It is deserving 

 of notice that so long as this class of soil is left undisturbed, 

 the sheep, although grazing sparsely, are in good health ; but no 

 sooner is it drained and limed, and put under such rotation as is 

 deemed best fitted to accelerate its being laid down again to 

 grass, than a strange class of diseases make their appearance 

 amongst the sheep confined to this land; amongst the most 

 conspicuous of these affections is this peculiar bone disease. 



" There is nothing either in the general health of the sheep, 

 their powers or manner of locomotion, or external appearance 

 of the bones, which afterwards show so much alteration of 

 structure, to attract attention, or even raise the suspicion that 

 the animals are not in good health and doing well. 



" The first indication that there is aught seriously wrong is in 

 all probability the finding some morning of one or more of the 

 flock helpless from a fractured limb ; or this condition may be 

 observed actually to occur while the sheep are being turned 

 by a dog in the usual course of telling and inspection. 



" The fractures, as a rule, occur in the long bones of the limbs. 

 On carefully examining these bones, there is frequently little to 

 be observed of an abnormal nature on their exterior surface. 







