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POPULAR SCIENCE MONTHLY. 



name of " transverse metacarpal," binds all 

 the fingers together and restricts their sep- 

 aration from each other in the transverse 

 plane of the hand. The great toe of the 

 ape is similarly not tied to the second toe as 

 the other toes are tied to one another and 

 restrained in their movements. The hallux 

 of the ape is therefore set free, and can, like 

 the thumb, be thrown into opposition and be 

 used as a prehensile digit. In the human 

 foot the hallux is tied to the second toe by 

 a continuation of the same transverse meta- 

 tarsal ligament that ties the smaller toes 

 together. Hence it is impossible to oppose 

 the great toe to the surface of the sole in 

 the way in which the thumb can be used, 

 and the movements of the digits in the 

 transverse plane of the foot are also greatly 



restricted. In the hand of both man and the 

 ape the joint between the metacarpal bone 

 of the thumb and the bone of the wrist is 

 concavo-convex, or saddle-shaped, and per- 

 mits of a considerable range of movements 

 in certain directions, and notably of the 

 movement of opposition. In the foot of man 

 the joint is not thus shaped, and the range 

 of movement is slight. One of the chief 

 factors in the production of the movement 

 of opposition is a special muscle, the. oppo- 

 nens pollicis, which is so adjusted as to draw 

 the entire digit over the surface of the palm. 

 In the foot of the anthropoid apes there is 

 not complete correspondence among the dif- 

 ferent species in the similar disposition for 

 moving the great toe, and in some it is al- 

 together absent, as it is in the foot of man. 



MINOR PARAGRAPHS. 



The excitement over the discoveries of 

 gold in the Klondike has caused attention to 

 be directed again to the search for the pre- 

 cious metal. Long neglected deposits are 

 re-examined, the gravels of farms are in- 

 spected, and bits of sparkling yellow dirt 

 are collected, to have it determined whether 

 there may not be real gold in them. The 

 officers of the mint in Philadelphia are kept 

 busy testing the specimens sent to them. 

 Hardly a day passes, we are told, that the 

 assayers are not called upon for this pur- 

 pose, and samples of supposed gold and sil- 

 ver quartz and of sand come into the mint 

 by mail and by express. These specimens in- 

 clude every variety of shining rock and dust 

 pyrites, mica, talc, common sand, and 

 rock sprinkled with crystals ; and along 

 with them often come letters which suggest 

 how bitter will be the disappointment of the 

 senders when they learn that the precious 

 stuff from which they anticipate so much is 

 only "fool's gold." They might learn the 

 real nature of their treasure nearer home, 

 but no jeweler's or metal worker's reply will 

 do for them. Nothing but what they con- 

 sider the highest expert authority will satisfy 

 them. 



The investigations by Prof. Wesley Mills 

 of the psychic development of the rabbit and 

 the cavy or guinea-pig are interpreted by him 

 as illustrating sharp contrasts at birth and 



for some time after in animals that in mature 

 life have much physically and psychically in 

 common. The cavy soon after birth is able 

 to care for itself and can maintain an inde- 

 pendent existence. The rabbit at birth is 

 blind, deaf, incapable of any considerable 

 locomotive power, and is, generally speaking, 

 in a perfectly helpless condition ; but it at- 

 tains comparative maturity in a month. So 

 simple is the psychic life of both animals 

 that there is little to note in them by way of 

 advance after they are a few weeks old. After 

 the first month of existence comparison with 

 the dog, cat, and allied creatures ceases to be 

 suggestive. The rodents are quite left be- 

 hind. They seem capable of little education 

 from man or Nature. 



In describing, in the American Associa- 

 tion, the Features of Recent Geology around 

 Detroit, Prof. Frank B. Taylor ascribed the 

 extreme flatness of the country mainly to the 

 fact that it was for a long time the bottom of 

 a lake. As the ice sheet retreated northward 

 in the Detroit Valley and northeastward on 

 Lake Erie, it blocked the escape of the water, 

 and a great lake was formed in front of the 

 ice, covering all the Detroit region and all 

 the lowlands around the western end of Lake 

 Erie. A terminal moraine crosses the Detroit 

 River in the vicinity of Detroit and Trenton, 

 but it was laid down in deep water and is 

 not a prominent feature. For a considerable 



