312 Alayow 



And further, from the very form of the curved 

 bones, we may gather that they grow equally on 

 both sides: for the bones have the form shown in 

 Fig. 4, which represents the tibia, where the concave 

 side, a^ is as long as the convex, b ; for if it were 

 otherwise, and the tibia had the form shown in Fig, 

 5, the thigh-bone, b, could not be supported on it with- 

 out manifest obliquity of the body, as may be seen 

 from the figure. 



We must, therefore, look for some other cause of 

 this curvature ; and to see our way more clearly, the 

 following points should be noted : — 



1st. We assert that in this disease the bones are 

 not to be reckoned among the parts affected in 

 respect to nutrition, for these are nourished and grow 

 no less than in healthy persons, as observation shows ; 

 for the blood alone suffices for their nutrition, and 

 there does not seem to be any need of the nervous 

 juice as in the nutrition of other parts ; for as bones 

 are not supposed to have any sensation of themselves, 

 they must be held to have little or nothing to do 

 with nerves. 



2nd. We take it for granted that in this disease, 

 the nervous and muscular parts do not grow at all 

 because of the lack of the nervous juice necessary for 

 their nutrition. 



These things being premised, let a in Plate IV.^ 

 Fig. 6, be the tibia, b the muscles attached to that 

 bone behind and forming the calf. As, then, the tibia^ 

 «, grows and lengthens, while at the same time it 

 is held, as by a string, by the muscles, which do not 

 grow in the same proportion, it follows necessarily 

 that that bone, strained by the shorter fibres of the 

 muscles, should be bent like a bow. I may illustrate 

 this hypothesis of mine by an example. If a string 



