530 TISSUES OF THE CONNECTIVE SUBSTANCE. 



On feeding sufficient calcium and phosphorus in the food ARON l found, 

 by strongly reducing the sodium and at the same time giving a large 

 .amount of potassium, that the development of the bones was below 

 normal. On the administration of madder the bones of the animal are 

 found to be colored red after a few days or weeks ; but these experiments 

 have not led to any positive conclusion in regard to the growth or metab- 

 olism in the bones. 



Under pathological conditions, as in rachitis and softening of the 

 bones, an ossein has been found which does not give any typical gelatin 

 on boiling with water. Otherwise pathological conditions seem to affect 

 chiefly the quantitative composition of the bones, and especially the 

 relation between the organic and the inorganic substance. In exos- 

 tosis and osteosclerosis the quantity of organic substance is generally 

 increased. In rachitis and osteomalacia the quantity of bone-earths is 

 considerably decreased. Attempts have been made to produce rachitis 

 in animals by the use of food deficient in lime. From experiments on 

 fully developed animals opposing results have been obtained. In 

 young, undeveloped animals ERWIN VOIT, ARON and SEBAUER and others 2 

 produced, by lack of lime-salts, a change similar to rachitis. In full- 

 grown animals the bones were changed after a long time because of 

 the lack of lime salts in the food, but did not become soft, only thinner 

 (osteoporosis). The attempts to remove the lime-salts from the bones 

 by the addition of lactic acid to the food have led to no positive results 

 (HEITZMANN, HEISS, BAGINSKY 3 ) . WEISKE, on the contrary, has shown, 

 by administering dilute sulphuric acid or monosodium phosphate with 

 the food (presupposing that the food gave no alkaline ash) to sheep and 

 rabbits, that the quantity of mineral bodies in the bones might be dimin- 

 ished. On feeding continuously for a long time with a food which 

 yielded an acid ash (cereal grains), WEISKE observed a diminution in 

 the mineral substances of the bones in full-grown herbivora. 4 A few 

 investigators are of the opinion that in rachitis, as in osteomalacia, 

 a solution of the lime-salts by means of lactic acid takes place. This 

 was suggested by the fact that O. WEBER and C. SCHMIDT 5 found lactic 

 acid in the cyst-like, altered bony substance in osteomalacia. 



Well-known investigators have disputed the possibility of the lime- 



1 Pfliiger's Arch., 106. 



2 Zeitschr. f. Biologie, 16; Aron and Sebauer, Bioch. Zeitschr., 8; A. Baginsky, 

 Arch. f. (Anat. u.) Physiol., 1881. 



8 Heitzmann, Maly's Jahresber., 3, 229; Heiss, Zeitschr. f. Biologie, 12; Baginsky, 

 Virchow's Arch., 87. 



4 See Maly's Jahresber., 22; also Weiske, Zeitschr. f. physiol. Chem., 20, and 

 Zeitschr. f. Biologie, 31. 



5 Cited from v. Gorup-Besanez, Lehrb. de. physiol. Chm., 4. Aufl. 



