Hunt and Wright: Pigmentation in Guinea-pig Hair 181 



the cortex of black and sepia hair and 

 its ahnost complete absence in red and 

 yellow, shows that the constitution of 

 the cortex imposes some obstacle in the 

 way of cortical pigment production in 

 red and yellow hair. The enzyme for 

 black overcomes this obstacle; therefore 

 pigment appears in the cortex of black 

 and sepia hair. It seems likely that 

 this obstacle is the slowing up of the 

 oxidation of. chromogens in the cortex. 

 This inhibiting action of the cortex is 



similar to the effect which the dilution 

 factors have u]5on pigment production. 

 The dilution factors reduce very little 

 the quantity of pigment in black hair, 

 but considerably diminish the amount 

 in red. Thus it seems plausible that there 

 is some characteristic peculiarity of the 

 cortex of guinea-pig hair which diminishes 

 the quantity of cortical granular pigment 

 in much the same way as the dilution 

 factors reduce the total granular pigment 

 content. 



Budding Incompatible Cottons. 



An experiment has come to light in 

 the field notes of the late R. M. Meade 

 which should be of interest to plant 

 breeders. Mr. Meade has been trying 

 for several years to secure hybrids be- 

 tween American Upland cotton, Gos- 

 sypium hirsuum, and two Asiatic spe- 

 cies, G. herbacemn and G. indicum. 

 From the standpoint of fertile seeds 

 these attempts proved to be unsuccess- 

 ful but in many instances the cross- 

 pollinated fruits remained on the plants 

 for several days longer than those not 

 pollinated, indicating that initial growth 

 had been stimulated by the application 

 of foreign pollen. 



That growth was started seemed to 

 mean that fertilization might have taken 

 place and that complete development 

 was prevented by some form of chemi- 

 cal incompatibility that caused the shed- 

 ding of the young bolls. Mr. Meade 

 ingeniously planned to overcome this 

 obstacle by budding one species upon 

 the other with the idea that the sap of 

 the stock would exert an influence upon 

 the chemical composition of the floral 

 organs of the budwood. No difficulties 

 were encountered in getting buds of 

 American Upland varieties to grow on 

 Asiatic stock and vice versa and several 

 successfully budded plants were secured. 

 Unfortunately the plants were budded 

 so late in the season that only one of the 

 resulting branches produced flowers and 

 this at a time when no flowers were open 

 on the stock plant. 



That the sap of the stock may alter 

 the chemical composition of the budded 

 branches was shown by an experiment 

 in budding two distinct Upland varie- 

 ties. The variety used for budwood 

 was Willet's Red Leaf. This variety 

 has dark red foliage and stems, which 

 are very distinct in color from those of 

 normal green varieties. The stock was 

 a normal green variety called Trice. 

 Several buds of the Willets's Red Leaf 

 were inserted on the Trice stock ; these 

 buds developed rapidly, producing large 

 well-formed leaves and branches. The 

 first leaves on the young budded 

 branches were red in color like the plant 

 from which the bud came but the suc- 

 ceeding leaves became lighter and lighter 

 in shade until at. the end of the season 

 they were only half as dark as those of 

 the parental plant which were all dark 

 red. This fact certainly seems to 

 support Mr. ]\Ieade's hypothesis that 

 the chemical composition of budded 

 branches might be influenced through 

 the stock, and leaves open the possibility 

 of accomplishing the hybridization of 

 American Upland and Asiatic species of 

 cotton. 



A more adequate investigation of this 

 interesting phenomenon is highly desir- 

 able. It is hoped that this method of 

 overcoming cross sterility, the testing 

 of which was interrupted by Mr. 

 ]\Ieade's untimely death, may be of in- 

 terest to other investigators. 



