278 CARNEGIE INSTITUTION 



7. Sport prepotency. 



(a) Cross an albino of a species of a genus which has white 

 species with the normal form ; observe potency of the sport. 



(b) Isolate an albino with nine normal individuals, four of 

 same sex as albino and five of the other. 



After many generations is the white swamped or does it prevail ? 



S. Do likes tend to breed together, t/ms establishing segregation 

 a7id divergence ? 



This could be observed in Leghorn fowls with rose comb and 

 with single comb ; also with Bufif fowls which have many white tail 

 and wing feathers and those which are almost free from them. 



p. Correlation. 



Select solely for one character. Are many correlated characters 

 also intensified? 



10. Determinate variation. 

 Grow one species, like Oenothera lamarckiana, known to have 

 determined variation, permitting all seeds to grow or selecting at 

 random for successive generations. Do the " petites especes" be- 

 come more prominent? 



Caution in all experiments. Record all deaths, in order that 

 any influence of natural selection in the results may be recognized. 



Equipment and Cost. 



The Vivarium would, in general aspects, resemble an agricultural 

 experiment station, and could be creditably and efficiently run within 

 the limits of the size and cost of the several agricultural stations 

 of the country. I shall outline what I have in mind, although either 

 retrenchment or enlargement would be possible within certain limits, 

 affecting only the amount and variety of results. 



(a) Greenhouse. This should be divided to give three temper- 

 atures, a large middle house with two smaller portions partitioned 

 off for cooler and hotter temperatures. All three portions should 

 be large enough to give space for aquaria, insect cages, and the like, 

 as well as for plants. 



{h) Barn. This should be long, narrow, and one story high. 

 On either side of the aisle would be wired cages, each communicat- 

 ing with wired runways outdoors, designed for cats, rabbits, guinea- 

 pigs, or fowls. 



