92 SCIENCE PROGRESS 



developed by arboreal life, might have extended his knowledge 

 from dead molluscs to the living ones has already been pointed 

 out. This function, together with the new uses for the hand 

 and foot, would further develop the brain, and thus the brain 

 became the organ of survival-value. As the shellfish could not 

 fight or run away, there was no call to develop great teeth, 

 swift legs, or any other organs of attack and defence. The 

 sands are clean, soft, and free from insects, so that the new 

 primate did not evolve callosities, nor did he become immune 

 to disease in the way that the lemurs and monkeys have done, 

 Protoman may have cracked shells with a stone instead of 

 using his teeth. Seashore food is nitrogenous, soft, nutritious, 

 and requires little mastication, Man's third molar is decadent ; 

 human babies can digest oysters, but not bananas, coconuts 

 or the cereals. All these are facts, and there may be a causal 

 relationship between them. 



Life on the seashore will also explain the loss of the hair. 

 Man's skin is not a monkey's skin minus the hair. It is far 

 better supplied with sweat glands, and man can thus survive 

 a degree of exposure to the sun which is speedily fatal to a 

 monkey. Man's naked skin is a conspicuous contrast to the 

 condition of all the other primates. Darwin and Haeckel more 

 or less cautiously attributed the change to sexual selection ; 

 other speculators, who wish to emphasise the ferocious beast 

 theory, have assigned the change to natural selection in order 

 to get rid of vermin. This is an unnecessary calumny, as no 

 healthy ape or monkey harbours lice or fleas — their regular 

 toilet is performed in order to pick out little flakes of dead 

 epithelium. Among the most primitive races, the Tasmanian 

 women used to wade and dive for shellfish, wrenching the 

 oysters off the rocks under water by means of a short wooden 

 chisel, and the shells were broken with a stone. The Fuegians 

 use much the same methods. If we suppose that as protoman 

 increased in stature, and so required more food, he did the 

 same, the loss of the hair is easily explained. When a hairy 

 animal comes out of the water the evaporation from the surface 

 chills the body, especially in the wind ; a naked animal dries 

 much more quickly and is less affected by the cold. The cold 

 body requires more food and is more liable to lung diseases. 

 Hence in times of scarcity this selective action would act rapidly. 

 The apes have a good coat of hair on their backs and heads, 

 but much less on the front and inner aspects. This is no 

 evidence against the theory of the seaside selective action, 

 because two other allied animals diverged in a similar way — the 

 elephant went naked and the mammoth developed a shaggy 

 coat. 



The primates are very subject to lung diseases. Most 



