July. 1928 



EVOLUTION 



Page Seven 



like capturing prey, be considered as purposeful or de- 

 signed, since the fundamental stimulus to activity re- 

 sults from an attempt to regain a disrupted balance. 

 Behaves Because She Must 

 If the behavior of amoeba depends upon the me- 

 chanism of its elemental substance and the mechanical 

 arrangement of its forces, where lies the evidence for 

 a psychic state? When we assume a "psychic state" 

 in the amoeba, we are merely projecting our own mental 

 experiences into it. The fact tiiat amoeba performs all 

 the physiological acts of the higher forms leads one to 

 believe, a priori, that some sort of volition influences its 

 reactions, but when the physio-chemical structure of its 

 body is kept in mind, no element of the entire reaction 

 system presents factors that lie beyond the reach of ob- 

 jective science, unless it be in the vastly more com- 



plicated and delicately adjusted balance that obtains in 

 a living colloidal suspension. It is true that all the ad- 

 justments of the living cell are too subtle to have yet 

 been observed by the human eye. However, the ability 

 of the human brain to analyze the structure of all things 

 that live increases at an uncanny rate. So we may look 

 forward to the time when we can write the chemical 

 formula that expresses the phenomenon of life. 



The only psychic state which the amoeba has may be 

 said to be the duration of the effect of a given stimulus, 

 a holding over into the future of an effect of the past, 

 a capacity which tends to become fixed through repeti- 

 tion, which develops with a neuromotor system, is be- 

 queathed to progeny, evolves, comes to reside as nascent 

 memory in special nervous organs and culminates in the 

 baffling mental life of man. 



Man's Fossil History 



By Hugh F. Munuo 



BONE for bone, and organ for organ, man is one of 

 the higher mammals. 



His body is made up of the same number of systems 

 (osseous, muscular, digestive, nervous, etc.) as is that 

 of the animal and is arranged in the same manner and 

 performs the same functions. Like the animal, his in- 

 dividual history begins in a single cell. He is nourished, 

 grows, reproduces and dies as do the animals. Within 

 their limited scope in the animal, he is assailed by the 

 same diseases and is cured by the same remedies. He 

 is fatigued by exertion, as they are, and he requires 

 periodical rest as they do; in fact, every one of his vital 

 processes has its exact counterpart in any one of tlie 

 higher mammals. It is, however, one thing to say that 

 he in general represents the animals, but it is quite an- 

 other to prove that he is related to them by descent. It 

 is now generally agreed that his immediate progenitor 

 is not to be found in any of the existing anthropoid 

 forms, but that he and they have developed from an an- 

 cestor common to them both, and his comparatively late 

 advent in geological time would lead us to expect that 

 here again intermediate forms could be found; and they 

 have been so found. 



In Asia the most primitive body of the human line or 

 the most human like body of the ape line is represented 

 by the fossil remains of the ape-man Pithecanthropus 

 Erectus found by Dubois in 1891, in an early Pleisto- 

 cene deposit at Trinil, Java. As was to be expected, the 

 cranial capacity of this fossil shows a stage more ad- 

 vanced than that of the ape, but less than that of man. 

 The volume of the brain cavity (between 850 and 950 

 cc.) indicates a brain of about 28 ounces in weight; the 

 forehead was more receding than in the modern chim- 

 panzee. As the maximum brain capacity of the gorilla 

 is only about 20 ounces fin volume between 500 and 

 600 cc.) and the average human brain weighs about ■19 

 ounces (1450 to 1550 cc.) and the smallest normal brain 

 of living man is probably never less than 30 ounces, it 

 ia clear that the brain capacity of Pithecanthropus is 

 more than halfway between that of the ape and of man. 



The most conservative estimate of the lapse of time 

 since the Pithecanthropus places it at about half a mil- 

 lion years ago. The next oldest human remains were 

 found in 1907 in some river deposits at Mauer, near 

 Heidelberg, in Baden. The specimen comprises only 

 the lower jaw with all of its teeth, yet it displays a 

 combination of characters not found in any other speci- 

 men, living or fossil. There is no chin prominence and 

 the shape of the whole jaw is more like that of a large 

 ape, yet the teeth are distinctly human. It was found asso- 

 ciated with a large number of fossils of animals now 

 extinct, which enables the life date to be placed at the 

 second inter-glacial period or 350,000 years ago. Other 

 fossil remains possessing more or less clearly defined 

 animal and human characteristics are the Neanderthal, 

 the Piltdown, and about half a dozen unnamed speci- 

 .niens discovered in various parts of the world. In semi- 

 desert Bechuanaland, South Africa, Prof. Raymond A. 

 Dart, of the Witwatersand University, has discovered an 

 almost perfect fossil skull of a type intermediate be- 

 tween the living anthropoid apes and man. The new 

 fossil has been named Australopithecus Africanus, but 

 ii will probably be known as the Faungo skull, from the 

 name of the comnmnity near where it was found. Geol- 

 ogists place the life date of this skull as some time dur- 

 ing the middle part of the Tertiary period, probably in 

 the late Miocene or the early Pliocene epoch. This 

 period, on a conservative estimate, is from two to three 

 million years ago, making it the most primitive human 

 fossil so far discovered. The Scientific American of 

 May, 1925, gives a very complete and illustrated de- 

 scription of this fossil, and comments as follows on the 

 discovery: "Thus is another part of the gap between 

 man and his simian ancestor filled in by an additional 

 'missing link.' Thus is Darwin's prediction that the di- 

 rect ancestor of man when found would prove to be 

 some form of forest-dwelling ape tied up tighter with 

 tangible evidence. Thus does the theory of evolution as 

 applied to man receive another and a weighty vindi- 

 cation." 



