90 THE STRUCTURE OF MAN 
It should, in passing, be noted that the mutual relationships between the 
muscles and bones are not absolutely similar in every single case, although a 
general agreement exists. The undeniably close connection between the 
modifications of two must not be regarded as that of cause and effect, but 
rather as the joint effect of a common cause. 
Clear signs of degeneration are also to be found in the other 
toes, and especially their middle phalanges, while the terminal and 
Fic. 64.—PosTERIOR END OF THE BoDY OF TWO HUMAN EMBRYOS, WITH THE 
LeFt Hinp-LiMB AND UMBILICAL CorD. 
A, at the end of the seventh week ; B, in the middle of the eighth week. The position 
of the great toe (I) is noteworthy. c.w., umbilical cord ; cc., coceygeal eminence. 
basal phalanges may be also affected. The second toe is mostly free 
from signs of degeneration: its middle phalanx shows a disposition 
to shorten, but it at the same time tends to become stronger 
rather than weaker. It might, therefore, be predicted of the 
human foot that it may end by possessing only two two-jointed 
toes, the great toe and its neighbour;* but the possibility of 
1 [It may be questioned whether it would not be more correct to predict, provided 
there is anything in this argument at all, that all the toes with the exception of the 
second may ultimately become two-jointed. | 
