670 THE POPULAR SCIENCE MONTHLY. 



saving of needless expenditure of force and energy which Dame Na- 

 ture practices. The study of human anatomy, which of course is one 

 in many points with the comparative science as applied to lower life, 

 reveals not a few instructive examples of this saving tendency in life's 

 ways. The human head, for example, is nicely balanced on the spine. 

 Compared with heads of lower type, this equipoise forms a prominent 

 feature of man's estate. The head-mass of dog, horse, or elephant 

 requires to be tied on, as it were, to the spine. Ligaments and muscu- 

 lar arrangements of complex nature perform their part in securing 

 that the front extremity of these forms should be safely adjusted. 

 But in man there is an absence of effort apparent in Nature's ways of 

 securing the desired end. The erect posture, too, is adjusted and 

 arranged for on principles of neat economy. The type of body is the 

 same as in lower life. Humanity appears before us as a modification, 

 an evolution, but in no sense a new creation. Man rises from his 

 "fore-legs" arms being identical, be it remarked, with the anterior 

 pair of limbs in lower life and speedily there ensues an adaptation of 

 means to ends, and all in the direction of the economical conversion 

 of the lower to the higher type of being. The head becomes balanced, 

 and not secured, as we have seen, and thus a saving of muscular power 

 is entailed. Adjustments of bones and joints take place, and the mus- 

 cles of one aspect, say the front, of the body, counterbalance the 

 action of those of the other aspect, the back ; and between the two 

 diverging tendencies the erect position is maintained practically with- 

 out effort. So, also, in the petty details of the work, Nature has not 

 been unmindful of her " saving clause." We see this latter fact illus- 

 trated in the disposition of the arrangements of foot and heel. One 

 may legitimately announce that man owes much to his head ; but the 

 truth is he owes a great deal of his mental comfort and physical econ- 

 omy to his heels. The heel-bone has become especially prominent in 

 man when compared with lower forms of quadruped life. It projects 

 far behind the mass of foot and leg, and thus forms a stable fulcrum 

 or support, whereon the body may rest. Here, again, economy of 

 ways and means is illustrated. There is no needless strain or active 

 muscular work involved in the maintenance of the erect posture in 

 man. It is largely a matter of equipoise, wrought out through a 

 scheme of adaptation which takes saving of power and energy as its 

 central idea. 



Physiological research lays bare many other points in human and 

 allied life which bear out the contention and principle that natural 

 economics is a powerful and prevailing reality of life. Muscles are 

 ordered, for example, on the plain principle of single acts and of 

 divided tasks. Thus a man bends his forearm on the upper arm large- 

 ly by aid of the familiar "biceps." This done, the "biceps" retires 

 from the field of work. The arm is straightened by the action of a 

 different muscle, the "triceps." So, also, with the shutting and open- 



