4 DISEASES OF BONES. 



circulation and accumulates in the tissues, checking the processes which 

 end in ossification or, in the case of adults, even leading to decalcification. 



It seems fairly well established that experimental administration of 

 lactic acid to animals causes diminution in the quantity of calcium salts 

 contained in the bones (Siedamgrotsky, Hofmeister). On the other hand 

 however Arloing and Tripier failed to produce rachitis experimentally. 



Bouchard revived this theory in a somewhat modified form. He con- 

 siders that calcium salts are absorbed as carbonates and chlorides and 

 phosphoric acid as phospho-glyceric acid. The reaction which these 

 compounds undergo within the organism ends in the formation of the 

 phosphate of calcium necessary to ossification, but this " i^hosphate of 

 ossification " cannot be deposited if the organism contains an excess of 

 lactic acid. 



Theory of inflammation. A third theory which until now has received 

 very little support is that called the theory of inflammation. The general 

 lesions which characterise rachitis are regarded as resulting from primary 

 attacks of ostitis and osteo-periostitis. The cause of these forms of 

 inflammation is not suggested. 



To the above views may be added that more recently emitted by 

 Dr. Chauniier, according to which rachitis is of an infectious nature. 

 Unfortunately no proof of this has yet been adduced. 



GENERAL DISEASES. 



RACHITIS. 



Eachitis is a disease of youth, and is common both to the human 

 species and to all domestic animals. It is characterised by irregularities in 

 development and by imperfect consolidation of the bones. The boundary 

 lietween rachitis and osseous cachexia is diflicult to define and in fact 

 at the present moment the two diseases can scarcely be defined with 

 exactitude. Eachitis again is often complicated with softening of the 

 bones, disease of the limbs, arrested development, etc., but it must not be 

 forgotten that although the irregularities in ossification and development 

 of the skeleton are the symptoms most striking to the eye, they do not stand 

 alone, and that from the point of view of development all the tissues, 

 including the muscles, are more or less affected and that most of the 

 physiological functions such as digestion and the secretion of urine are 

 deranged. 



Etiology. One of the principal causes suggested is that of heredity, 

 and so far as human beings are concerned, one seldom fails to discover 

 the rachitic taint. Certainly the offspring of individuals marked by any 

 debilita.ting disease like alcoholism, tuberculosis, syphilis, etc., are poorly 



