'488 



Dr. D. J. Cunningham. 



and as equal to 100.* A lumbar vertebra, therefore, with an index of 

 .100, may be regarded as neutral; it is equally deep in front and 

 behind, and can in no way contribute to the formation of a curve in 

 the antero-posterior direction. A vertebra, on the other hand, with 

 an index of 100 + , is shaped in a fashion unfavourable to the forma- 

 tion of a curve with the convexity directed forwards ; its posterior 

 vertical depth is greater than its anterior vertical depth. Again, a 

 vertebra with an index of 100 is moulded in a manner favourable 

 to the formation of a curve with the convexity looking forwards. It 

 .is deeper in front than behind. 



In seventy-six European spines, and in seventeen spines of abori- 

 .ginal Australians, the average indices obtained for the several lumbar 

 vertebrae were as follows : 



Lumbo-vertebral Index. 



The difference brought out by these figures is very marked. Indeed, 

 in this respect the Europeans and Australians constitute the two 

 extremes : no race shows an index lower than that of the European, 

 and no race presents an index higher than that of the Australian. 



In the investigations which I made three years ago into the con- 

 stitution of the lumbar curve in Man and the Apes, I was very early 

 convinced that little could be learned regarding the character and 

 degree of the curve from the lumbo- vertebral index. I was led to 

 adopt this conclusion as the following facts became apparent : 



1. In European spines a high index is not unfrequently associated 

 with a high degree of curvature. 



2. In the Chimpanzee, in which the lumbo- vertebral index is so high 



* ' Cunningham Memoir,' No. 2, Royal Irish Academy. " The Lumbar Curve 

 in Man and the Apes," by D. J. Cunningham, M.D. ' Zoology of the Voyage of 

 H.M.S. " Challenger," Part XL VII.' Sir Wm. Turner's " Keport on the Human 

 Skeletons, Part II," p. 67. 



