752 FRANCIS H. McCRUDDEN 



only a small portion of the bone, in which case the result is osteitis de- 

 formans. 



This point of view renders adolescent rickets more intelligible, and 

 serves to clear up the controversy regarding so-called infantile osteoma- 

 lacia. Rehn(a)(&), His(rf), Siegert, and von Recklinghausen(&) have 

 reported certain cases which they differentiated from rickets and 

 called infantile osteomalacia, a diagnosis disputed by Ziegler, who 

 called the condition rickets. From the old point of view, implying 

 an essential difference in the nature of the process in the two diseases, 

 the controversy had some significance. From our point of view it is not 

 significant; the difference between rickets and infantile osteomalacia is 

 probably largely one of severity. In a severe enough case of rickets, the 

 body may fail to supply sufficient lime salts, not only to uncalcified bones 

 and parts of bones which are due to become calcified, but may also destroy 

 bone which has already become calcified, and lay down new osteoid tissue 

 instead. 



The Cause of Abnormal Bone Metabolism. The causes which have 

 been conjectured as responsible for the abnormal bone metabolism in 

 osteomalacia, rickets and similar conditions, may be divided into exoge- 

 nous agencies of a general nature, such as bad hygienic environment 

 damp dwellings, lack of clothing, poor or insufficient food, hard work, care, 

 repeated pregnancies, protracted lactation, or combinations of two or more 

 of these agencies; exogenous agencies of a specific nature infection, fer- 

 ments, presence of certain substances in the diet, lack of calcium in the 

 diet, lack of certain vitamines; and endogenous agencies disturbance of 

 internal secretion, acid formation. 



The hypotheses mostly widely accepted for the etiology of osteomalacia 

 are, first, that the actual process is due to the action of an acid, commonly 

 believed to be lactic acid; and second, that the condition is a disease of 

 the ovaries. But there is evidence enough to disprove both of these 

 hypotheses. 



Acid Action in Osteomalacia. The hypothesis, that the disappear- 

 ance of lime salts from the bone in osteomalacia is due to the action of an 

 acid, is based on the assumption that the process is one of halisteresis, 

 whereby the mineral constituents are dissolved, and the organic matrix of 

 the bone left behind a hypothesis which falls with the rejection of the 

 halisteresis assumption. Furthermore, we know now that blood and tissue 

 fluids do not become acid, that in the phosphate and carbonate buffer 

 mixtures we have a delicate mechanism for preserving within very narrow 

 limits the neutral reaction of the blood and tissue fluids. But, since 

 the halisteresis hypothesis had an apparent confirmation in the alleged dis- 

 covery of lactic acid in the bones and urine in osteomalacia, we must 

 examine the evidence on this point. Schmidt states that he found 

 lactic acid in the bones, and Moers and Muck and Langendorff and 



