394 INFLAMMATION. 



Marchand, Ragsky, Lehman, Simon, and others, found free 

 lactic acid in the urine of persons affected with either rachitis or 

 osteomalacia. C. Schmidt discovered lactic acid in the liquid 

 of malacic shaft-bones which had been transformed into globular 

 cysts. Based upon these researches I commenced, in April, 1872, 

 a series of experiments on the influence of internal administra- 

 tion and subcutaneous injection of lactic acid on the bones of 

 living animals. These experiments were continued till the end 

 of October, 1873, and were made on five dogs, seven cats, two 

 rabbits, and one squirrel. 



The result was that in dogs and cats, in the second week of 

 the administration of lactic acid, no matter whether introduced 

 with the food or by subcutaneous injection, the quantity of 

 lime-salts given with food being simultaneously reduced, swell- 

 ings appeared in the epiphyses of the shaft-bones of the extremi- 

 ties, and at the insertions of the rib-bones into their cartilages. 

 The enlargement of the epiphyses and the ribs increased con- 

 tinually up to the fourth and fifth week, and at the same 

 time curvatures of the bones of the extremities were noticed. 

 Catarrhal inflammation of the conjunctiva, the bronchi, the 

 stomach, and the intestines, emaciation and twitching of the 

 extremities, were the concomitant symptoms. 



The microscopical examination of the epiphyses demonstrated 

 the identity of this pathological process with that seen in the 

 epiphyses of rachitic children. 



On continuing the administration of lactic acid, the enlarge- 

 ment of the epiphyses of the long-bones decreased, and the 

 shafts themselves became, to a certain degree, less curved, while 

 catarrhal inflammations of the mucous membranes occurred 

 repeatedly. After four or five months, softening of the shaft- 

 bones set in to such a degree as to render the bones as pliable 

 as willow-boughs. The microscopical examination of the bones, 

 after administration of lactic acid, continued for four to eleven 

 months, showed a condition of things identical to that seen in 

 human beings, dead of osteomalacia. 



In the three herbivorous animals no swelling of the epiphyses 

 was observable. One rabbit died in the third month, the other in 

 the fifth month, of the administration of lactic acid, both having 

 symptoms of inanition. In the bones of these animals there were 

 no marked signs of rachitis or malacia. The squirrel, on the con- 

 trary, which died after thirteen months' treatment with lactic acid, 

 exhibited, in a high degree, the characteristics of osteomalacia. 



