METABOLISM IN DISEASES OF BONES AND JOINTS 761 



of the period between weaning and beginning improvement (w to i) in 

 succeeding pregnancies is referred to later on. 



Etiology of Other Disturbances of Bone Metabolism. In puerperal 

 osteomalacia the bone changes are greater than in other forms of dis- 

 turbed bone metabolism; the cause of the disturbance is more apparent; 

 and it has been more thoroughly studied. It. serves, therefore, as the 

 best type in discussing pathological bone metabolism. But other forms 

 of disturbed bone metabolism fit, quite properly, into the theory of bone 

 metabolism outlined here. Causes other than pregnancy and lactation 

 may be responsible for a drain of calcium from the bones, and result in 

 osteomalacia. Henning, and more recently Berger(6), have pointed out 

 that the formation of lime stones, especially in the kidney, is a very 

 common accompaniment of osteomalacia. These kidney lime stones are 

 so large and so common in such cases that the condition has been named 

 calcareous metastasis (Boulby). In one such case reported by Daires- 

 Colley in a ten year old girl, the renal calculi were so large and abundant 

 as to lead to suppurative pyelitis and eventually death. Softening of 

 the bone has been observed at autopsy to accompany calcification of the 

 muscles in myositis ossificans progressiva (Mays, Rabeck). More re- 

 cently rontgenographs have shown rarefaction of the bone in this disease 

 (Krause and Trappe). A case of ostitis rarificans has been reported by 

 Jadassohn following calcification in the papillary muscles, kidneys, lungs, 

 spleen, skin. 



Decalcification of the bones (shown by bone analysis) results in cases 

 of obstructive jaundice from the need of calcium salts to neutralize the 

 toxic effects of the bile acids (King, Bigelow and Pierce). Osteomalacia 

 appears, too, in animals, especially dogs, with permanent biliary fistula as 

 the result of the loss of calcium salts (von Recklinghausen(c), Looser(&). 

 Seidel, Lenormant). The fact that fractures in such cases heal with 

 osteoid tissue, and not real bone, is in harmony with the theory of bone 

 metabolism outlined in this chapter, and lends further weight to it. 



Etienne and Duplain(a) (&) have noted a connection between 

 osteomalacia and severe arteriosclerosis. They report the case of a woman 

 with very marked arteriosclerosis and with a large calcified myoma, in 

 whom the osteomalacia came on just after the arteriosclerosis. The 

 decalcification in this case was greatest in the vertebrae at the level of 

 the most intense calcification of the aorta. These writers point out that 

 the calcium content of the bones of old people with severe arteriosclerosis 

 is less than that of other old people. 



Trevelyan has observed that osteoporosis sometimes accompanies the 

 increased bone formation in acromegaly. 



In one case reported by McCrudden, the flux of calcium was appar- 

 ently induced by the growth of bony tumors (McCrudden and Fales(a)). 

 An extract from the history and two rontgenographs from this case follow. 



