KICKETS. 



179 



a peculiarly ludicrous manner, the sternum almost touching the 

 ground. In foals and calves, the shafts of the metacarpals are 

 the first to give way, the curvatures being from within out- 

 wards; thus the knees are thrown outwards, and the toes 

 drawn inwards. The articulations and extremities of the bones 

 sometimes become enlarged, hot, and painful ; causing so much 

 lameness that the little 

 animal merely touches the 

 ground with the toes of the 

 affected limbs, and as the 

 animal increases in size the 

 spinal column becomes too 

 feeble to bear the weight 

 of the body, and symptoms 

 of paralysis are observable. 



When the bones of the 

 posterior extremities are 

 affected, the toes are turned 

 outwards, the hocks in- 

 wards: the points of the 

 calci almost touching each 

 other; the animal being 

 what is termed "cow- 

 hocked," the metatarsals 

 at their middle 

 bent inwards and rather 

 backwards. In the dog the humeri — the bones most commonly 

 involved — are bent laterally by the action of the muscles, their 

 inferior extremities being pulled upwards and outwards as v 

 specimens 29 and 30, and the lower third of the shafts curved 

 inwards, the curvatures being so great as almost to bend the 

 bones completely upon themselves. 



In rickets, not only is there a deficiency of the inorganic 

 elements of the bones originally — namely, the phosphate and 

 carbonate of lime — but there is a want of power to assimilate 

 these salts; for during the progress of the disease there is 

 inordinate excretion of them from the system, as shown by 

 deposits in the urine. The structure of the bones is soft, 

 cartilaginous, and open : but if the animal be allowed to 



Fig. 30. 



■I • Figs. 29 and .30 illustrate the bent condition 



Oeinj., qJ ^jjg humerus in rickety dogs. 



