94 THE POPULAR SCIENCE MONTHLY 



ments; and these are of supreme importance even yet. He who jumps 

 quickest out of the way of the runaway horse escapes with his life; 

 the old gentleman, whose reaction-time age has lengthened, does not 

 step aside from the carelessly driven motor-car sufficiently perfectly, 

 and so gets run over. Those men who after harpooning the whale got 

 their boat most quickly out of the reach of his tail, were most likely to 

 reach the big ship in safety. He burns his fingers least who most 

 rapidly drops the hot coal. 



While, now-a-days, shortness of reaction-time may only occasionally 

 contribute to the actual saving of life, yet it does assuredly contribute 

 towards what is called " success " in life. He who most quickly grasps 

 a situation of danger and acts accordingly, has an advantage over his 

 neighbor with the more sluggishly reacting nervous system. 



It is obviously by his development of intelligence — a power of the 

 nervous system — that man has not only conquered nature, animate 

 and inaminate, but has learned to use its forces, even the most hostile, 

 in the interests of his own comfort and prosperity. 



Our first line of defence is, then, mental; and the elements of time 

 and precision are all important. 



We have, however, to reckon with foes far more subtle and more 

 often met with than the thunder-bolt, the lion, the bear or the electric 

 eel. In some parts of the world, the living things that can poison us 

 are very numerous — venomous snakes, scorpions, countless insects, all 

 ready to pour their poison and acids into our skins. Mankind has 

 learned that alkali will neutralize their acid, and has in these latter 

 days discovered how to manufacture an antivenin, to counteract the 

 venin or venom of the serpents. 



We fight chemical injuries by chemical means. But all these sources 

 of danger or injury are insignificant compared with those which are 

 absolutely and forever beyond the ken of our senses. In common with 

 all other living things, we are surrounded by parasites and preyed 

 upon by them continually. It seems a law of animate nature that any 

 given living thing, vegetable or animal, should have its particular 

 parasite or parasites. For even the vegetables have parasites: the 

 potato has the potato-blight, a fungus; the vine has its phylloxera, 

 another fungus, and so on. The lower plants prey on the higher, the 

 higher on the highest. Fungi and moulds are parasites on both plants 

 and animals. Animals are parasitic on plants : grubs eat the roots and 

 the buds of flowers, the aphides destroy the roses, the Colorado beetle 

 devours the potato. The gooseberry moth strips the leaves off the goose- 

 berry plant; the oak has its galls, everything its blemishes. To such 

 an extent is all this recognized now-a-days that a department of botany, 

 economic vegetable parasitology, has arisen within the last few years. 

 Expert botanists are studying the conditions under which these pests 



