51 



aphides. "During the warmth of summer, when food is abund- 

 dant, these insects produce parthenogenetically nothing but 

 females, while in the famines of later autumn they give birth to 

 males. In striking confirmation of this fact it has been proved 

 that in a Conservatory where aphides enjoy perpetual summer, 

 the parthenogenetic successsion of female continued to go on for 

 four years, and stopped only when the temperature was lowered 

 and food diminished." 



In my own experiments and observations I have found sev- 

 eral things influencing sex that I have not found mentioned by 

 the authorities. One of these is affinity. I have found that 

 where there is perfect affinity and the birds are happy and con- 

 tented, the conditions are right for the production of females ; but 

 where the birds are not well mated and frequent quarrels ensue 

 the offspring are likely to be largely males. Another thing is 

 freedom from disturbance and fear. Where hens are kept stirred 

 up by the presence of strangers or shifted frequently from place 

 to place their eggs are quite sure to hatch an excess of males. 

 The quieter you can keep your hens the more pullets you will get.. 



The greater the number of females to a male the more pullets. 

 I know a man who mated two roosters to 118 hens, and out of 

 135 chickens hatched 107 were females. 



Now let me sum up all that has been said in the language of 

 another : "Such conditions as deficient or abnormal food, low tem- 

 perature, deficient light, moisture and the like, are obviously such 

 as would tend to induce a preponderance of waste over repair, a 

 katabolic habit of body and these conditions tend to result in 

 the production of males. Similarly, the approved 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 conditions result in the production of females. With 

 some element of uncertainty we may also include the influence of 

 the age and of physiological 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 katdbotisnt 

 (or waste) tend to result in the production of males, as those 

 favoring anabolisrn (or repair) similarly increase the probability 



of females." 



This is the law of sex, so far as it can be stated at present. 



