94--2 Rachitis. 



is retarded and irregular. All these symptoms may be un- 

 noticed, so that attention is not attracted to the disease until 

 the motor disturbances commence. The aching in the Ijones, 

 Avhich occurs before the changes in shape, causes the animals to 

 step about restlessly, while at the same time they move gingerly 

 and their walk is stiff or lame; they lie much on the ground 

 and dislike to rise. Especially pigs, less so kids and lambs, 

 and at times other animals do not use their posterior extremi- 

 ties, or indeed, all extremities, at all. They seem paralyzed, 

 and on being forced to rise they crawl about sciuealing aloud. 

 (The cases of paralysis in chicks, which AVilke diagnosed as 

 poliomyelitis anterior, probably had a similar origin.) Smaller 

 animals often assume a kneeling position (Fig. 160). These 

 motor disturbances increase with the progress of the disease 

 and when the shape of the bones commences to be altered. 



Fig. 160. Rachitis (of pig). Aside from the motor disturbances the pig showed 

 slight snuffling. 



In certain cases the disease becomes apparent through 

 severe nervous disturbances, as was pointed out by Klimmer & 

 Schmidt for osteomalacia and as the authors observed fre- 

 quently in calves and pigs. The affected animals suddenly 

 become somnolent, they stagger and even fall down, and occa- 

 sionally develop generalized tonic-clonic muscular convulsions, 

 which however may also be produced by external influences. 

 Such attacks either terminate, in some 6 or 8 hours, Avith the 

 death of the animal or are repeated a few times in the course 

 of some days or weeks before death results, or then they do 

 not appear at all, but the typical sjanptoms of the disease be- 

 come evident at once. 



The changes in form are, at least in the beginning, most 

 striking in the long bones of the extremities. The epiphyses 

 are enlarged and it looks as though the joints themselves were 



