INORGANIC FOODS. 373 



precipitate. By boiling and concentrating the filtrate, the globulin and 

 albumin of milk are obtained. These proteins likewise contain but little 

 lime. It is not impossible, but quite probable, that the small amounts of 

 calcium contained in these precipitates are merely carried down mechani- 

 cally, without there being any state of combination between the albumin 

 or globulin and the calcium. The greater part of the lime is found in the 

 nitrate from the two precipitations. After the removal of the casein and 

 of the two other protein substances, the addition of oxalic acid at once 

 causes the formation of a precipitate. The filtrate from this last precipi- 

 tate of calcium oxalate was evaporated to dryness and ignited with sodium 

 carbonate in order to remove the calcium from any organic substance 

 which might not have been precipitable by oxalic acid. This ash, however, 

 contained merely a trace of calcium. This shows that the calcium, if 

 originally combined with protein, must be present in some loose salt-like 

 combination such that even dilute acetic acid suffices to set it free. It 

 has, however, not been established definitely whether some other organic 

 substance in the milk may not serve to keep calcium in solution in the 

 presence of phosphoric acid. 1 



From these observations of Bunge we may say that it is undoubtedly 

 true that lime is absorb able and assimilable as such. Against this assump- 

 tion the objection may be raised that it is possible that the lime in the 

 intestine first of all enters into combination with some organic substance 

 and is then ready for absorption, and that the latter process depends 

 entirely upon the formation of such an organic compound. On the other 

 hand, it may be said that even in such a case the manner of combination 

 in the alimentary canal must be a weak one, for it is not to be assumed 

 that any sort of firm combination is formed. Such a loose form of com- 

 bination would have the effect of keeping the calcium in solution, but it is 

 perfectly certain that they have no other effect upon the process of assimi- 

 lation. We cannot be wrong in assuming that every calcium compound 

 which can be converted into a soluble condition in the intestine is capable 

 of being absorbed and assimilated. 



We have up to now found no reason for believing that the disease of 

 rickets is due to a diminished capacity for absorption on the part of the 

 alimentary canal. 2 It is far more probable that the cause of the faulty 

 calcification of the bones is due to a diminished assimilation of lime. It 

 is highly probable that the cause of this is not to be sought in an unsuitable 

 condition of the calcium salts that are at the disposal of the tissues. It is 



1 L. Vaudin, Ann. inst. Pasteur, 8, 502 (1894), has observed that the amount of 

 citric acid in milk is proportional to the lime content. It is altogether out of the ques- 

 tion to believe that the lime is simply dissolved by this acid, but possibly citric acid in 

 conjunction with other organic substances may serve to keep the lime in solution. 



2 T. G. Rey: Deut. med. Wochschr. 35, 569 (1895). 



