556 MUSGRAVE AND SISON. 



Is it not logical to reason a posteriori that the most probable cause 

 of the deformity is primary inflammation and destruction of the secondary 

 center of ossification situated between the epiphyses and diaphyses, result- 

 ing in premature ossification ? 



Another possible explanation of the deformity is that metabolic dis- 

 turbances in the epiphysial cartilages have been induced by variola 

 without primary, destructive lesions appearing in the cartilage itself. 

 However, such a conclusion is hardly tenable if we remember that the 

 articular cartilages of the affected bones show positive signs of irregular 

 enlargement, bearing on them evidences of the ravages of a preexisting 

 inflammatory process underlying the whole trouble. 



The special predisposition of the bones of the forearms and hands 

 to this complication remains as the most difficult fact to explain. 

 So far as we have been able to obesrve, the change does not occur 

 in bones other than those which have already been mentioned; and 

 such a complication is always seen in infancy and childhood during the 

 period of active growth, of the bones. 



Additional note. — We have mentioned the shortening of the bones 

 of the forearms, and also deformities in their articular surfaces ; and while 

 our article was in the press two more cases of bone lesion in smallpox 

 of different character from those already mentioned came to our notice, 

 the pictures of which are here respresented. One is that of a girl 

 (see Plate IV, figure 1) about 9 years of age, who contracted smallpox 

 when she was about 3 years old. As a result of the disease, she developed 

 complete ankylosis of the. right elbow-joint and partial of the left. 

 Whether the ankylosis is bony or fibrous in character is difficult to say, 

 though there are reasons for believing that the ankylosis in the right 

 elbow-joint is of a bony character, as it is not possible to elicit the 

 slightest motion in any direction, while that of the left is evidently pro- 

 duced by shortening of the particular ligaments of the elbow-joint. 



The other case is that of a man (see Plate IV, figure 2) about 50 years 

 old who contracted smallpox at the age of about 7 years, with a resulting 

 complication of shortening of both humeral bones. 



