OOb PROF. T. WINGATE TODD OX OSTEOMALACIA. 



lesion, and therefore localised, as in the variety appearing after 

 trauma. 



It may develop in connection with giant-celled sarcoma and be 

 more generalised in type (Schonenberger, 8). 



It may occur in the so-called spontaneous form, such as is seen 

 in animals in captivity. 



The last-mentioned variety is certainly not a simple decalcifi- 

 cation. There is absorption of osseous substance with rarefaction 

 of the tissue. The process starts from the marrow-cavity and 

 involves first spongy and later compact bone. The Haversian 

 systems disappear and the bone becomes fibrillar in character and 

 later is transformed into fibrous tissue. 



An intermediate hyaline change is shown in places. All these 

 changes point to a revolution in the constitution of bone as a 

 whole, which is acconiipanied by changes in the marrow and 

 periosteum, as already described. Similar changes in bony 

 tissue are to be observed in ostitis fibi-osa and leprosy. For it 

 has been my good fortune to be able to investigate all three 

 diseases at the same time. The clinical symptoms in these cases 

 of generalised bone-softening, which I have described as osteo- 

 malacia, suggest a nervous origin. The obvious inference to be 

 drawn from the histological picture in leprosy is that in the last- 

 named disease the bone-changes are certainly trophic in character. 

 I would emphasise the fact that we are as yet ill-acquainted with 

 the symptoms consequent on lesions to the sympathetic nervous 

 system. But there would seem to be ample confirmation of nerve- 

 lesion in the histological changes found in the nerve-bundles by 

 Gayet and Bonnet (1). Moreover, the intimal proliferation de- 

 scribed by these authors in the vessels of the nerve-trunks may 

 be produced by a lesion in the sympathetic nerves, as I have 

 recently been enabled to show (9). 



If the disease is infectious, the incubation -period must be con- 

 siderable, for it seems to appear spontaneously in anima,ls which 

 have been isolated for a long while. After inoculation, Morpurgo 

 found the animal became ill in a week or two. Such evidence as 

 we have points to the nervous system as the seat of primaiy 

 disease, whether it be infectious or not, and suggests that the 

 bone-changes are consequent on nervous lesion. Treatment is 

 unsatisfactory. Dr. Fox, of Philadelphia, has recently adminis- 

 tered calcium lacto-phosphate and adrenalin, separately and in 

 combination, to animals sufliering from the disorder in the 

 Philadelphia collection, but without success (10). 



In making observations on the living animals Messrs. Antliff 

 and Readinger, keepers of the monkey-houses at Manchester and 

 Cleveland respectively, have rendered generous assistance. The 

 histological sections are the Avork of Mr. Gooding, of the Ana- 

 tomical Department of Manchester. Mr. J. C. Miller, of the 

 Laboratoiy here in Cleveland, has assisted me in gathering and 

 abstracting the literature. To all these gentlemen, I would 

 therefoi'e express my obligation. 



