328 STUDIES, SCIENTIFIC AND SOCIAL chap. 



organ. I presume the original eye of the ancestral 

 Proteus must have had its three distinct sets of nerves — 

 those of vision, of sensation, and of motion — involving in 

 their normal use the expenditure of a considerable amount 

 of nervous energy, besides the various muscles and blood- 

 vessels connected with it. To measure the benefit to be 

 derived from the entire suppression of such a complex 

 organ, when it became useless, as no more than from the 

 gain of so many grains of simple muscular tissue, appears 

 to me to be an extraordinary misconception of the condi- 

 tions of the problem. 



The second oversight is in ignoring the tremendously 

 severe struggle for existence that would necessarily arise 

 when an animal which had heretofore had the full use of 

 eyes in obtaining food, avoiding danger, and finding its 

 mate, had to enter upon a perfectly new kind of existence, 

 in total darkness, and, moreover, in a place where all kinds 

 of vegetable or animal life were so scanty that the wonder 

 is how those individuals who were first carried into the 

 cavern escaped starvation. Under such conditions as 

 these, would not the various modes of reduction of the 

 eyes above suggested act with an energy and rapidity far 

 beyond their action under normal conditions ? And might 

 we not expect the most extreme variations in the direction 

 of the abortion of the eye and of its connected tissues, 

 muscles, and nerves, to have an exceptional value when 

 the food required for building up the organism could only 

 be obtained with the greatest difficulty and in the most 

 limited quantities ? Under such conditions I should not 

 be surprised if the greater part of the actual eye-reduction 

 had been effected in fifty or a hundred years, instead of in 

 two thousand. But whether this were fche case or no, it 

 will, I think, be admitted that to ignore all these very ex- 

 ceptional conditions, and to argue the case as if the whole 

 matter were one of the economy of a few grains of tissue to 

 an animal whose food-supply was normal, does not add 

 anything to the evidence for the inheritance of acquired 

 variations. 



