44 THE EVOLUTION OF SEX. 



general conclusion most probable — that adverse circumstances, 

 especially of nutrition, but also including age and the like, tend to 

 tiie production of males, the reverse conditions favoring females. 



{b) As to the reproductive elements, a highly nourished ovum, 

 compared with one less favorably conditioned, in every probability will 

 tend to a female rather than to a male development. Fertilization, 

 when the ovum is fresh and vigorous, before waste has begun to set 

 in, will corroborate the same tendency. 



(e) Then if we accept Sutton's opinion as to the transitory hermaph- 

 rodite period in most animals, from which the transition to unisex- 

 uaiity is effected by the hypertrophy of the female side or preponder- 

 ance of the male in respective cases, the vast importance of early 

 environmental influences must be allowed. The longer the period of 

 sexual indifference (though this term be an objectionable one) con- 

 tinues, the more important must be those outside factors, whether 

 directly operative or indirectly through the parent. Here again, 

 then, favorable conditions of nutrition, temperature, and the like, tend 

 toward the production of females, the reverse increase the probability 

 of male preponderance. 



The general conclusion, then, more or less clearly grasped by 

 numerous investigaters, is that favorable nutritive conditions tend to 

 produce females, and unfavorable conditions males. 



IV. Let us express this, however, in more precise language. 

 Such conditions as deficient or abnormal food, high temperature, 

 deficient light, moisture, and the like, are obviously such as would 

 tend to produce a preponderance of waste over repair, — a katabolL 

 habit of body, — and these conditions tend to result in the production 

 of males. Similarly, the opposed set of factors, such as abundant 

 and rich nutrition, abundant light and moisture, favor constructive 

 processes, — that is, make for an anabolic habit, — and these condi- 

 tions result in the production of females. With some element 01 

 uncertainty, we may also include the influence of the age and physio- 

 logical prime of either sex, and of the period of fertilization. But 

 the general conclusion is tolerably secure — that in the determination 

 of sex, influences inducing katabolism tend to result in production 01 

 males, as those favoring anabolism similarly increase the probability 

 of females. 



V. This is not all, however: the above conclusion is indeed valu- 

 able, but it acquires a deeper significance when we take it in connec- 

 tion with the result of a previous chapter. There it was seen, as the 

 conclusion of an independent induction, that the males were forms 

 of smaller size, more active habit, higher temperature, shorter life, 

 &c. ; and that the females were the larger, more passive, vegetative, 



