ITS COMPOSITION IN DISEASES. 2? 



may add my own,* we are still in ignorance of the pathological 

 process "and the morbid product of true rachitis. Our analyses are 

 only so far accordant, that all agree in assuming that rachitis 

 induces a considerable diminution of the mineral constituents of 

 the bones, although it still remains to be decided whether this 

 diminution may not be in part a relative one, depending merely 

 upon an increase of cartilage. The assumption of many patholo- 

 gical anatomists, that the rachitic process is connected with true 

 hypertrophy of the bone-cartilage, must at the present day be 

 regarded as, to say the least, very improbable ; for when rachitic 

 bones, which have been only moderately macerated and deprived of 

 their fat, are examined in thin sections under the microscope, the 

 Haversian canals and lacuna (bone-corpuscles) are not found to be 

 filled with organic matter, but are either empty or dilated. If we 

 calculate the analysis of an imperfectly macerated bone, containing 

 all its fat (and the gelatinous substance effused into the medullary 

 canals) for 100 parts, we shall indeed obtain an absolute excess for 

 the organic constituents, and a relative deficiency for the inorganic 

 matters; but these relations do not prove the existence of hyper- 

 trophy of the cartilage. Such a condition can only be microsco- 

 pically and chemically shown in those rachitic bones which exhibit 

 a tendency to healing through sclerosis ; an absolute augmentation 

 of the cartilage can be detected only in these cases, and not in the 

 highest stage of the special rachitic process. Hypertrophy of the 

 cartilage constitutes the basis, not of softening of the bones, but 

 of osteosclerosis, more especially when it occurs after rachitis, or 

 after osteoporosis. The nature of the cartilage generally re- 

 mains altogether unchanged in rachitis ; but Marchand and I have 

 observed cases of highly developed rachitis, in which no glutin 

 could be extracted from the bones, although after prolonged boil- 

 ing, I obtained a slightly gelatinising substance which yielded 

 some of the reactions of chondrin. An exact determination of the 

 relations of the earthy constituents of rachitic bones is the more 

 important from the light which they appear to throw on other pro- 

 cesses, and on the nature of rachitis itself. The carbonate of lime 

 appears from several analyses to diminish proportionally to the 

 earthy phosphates, but other analyses (as for instance those made by 

 Marchand and myself) yield a higher amount for the carbonate of 

 lime than the normal proportion. Although the phosphate of lime 

 is often much diminished, the rachitic process cannot be con- 

 ditional upon the occurrence of free acid, as has been assumed 

 * Schmidt's Jahrb. der ges. Med. Bd. 38, 8. 280. 



