TACTICS IN PIGMENT-CELL RESEARCH 



337 



pink-eyed dilution (/»), maltese dilution (d), and brown (b) loci; giving us a total of 

 eight color genotypes. We also used albinos as controls to provide baseline measure- 

 ments. 396 



Fig. 47. Sample oxygen -consumption curves during the incubation in vitro of skin 



SUBSAMPLES OBTAINED FROM TWO DIFFERENT COLOR GENOTYPES. 



180 



160 



140 



120 



O 100 



o 80 



60 



40 



20 _ 



THEORETICAL MAXIMUM NET 2 CONSUMPTION 

 TYROSINE: 232 Jtl (5 ATOMS/MOLECULE) 

 D0PA: 170 Mi (4 ATOMS/MOLECULE) 



2 3 4 5 



TIME (HOURS) 



Our first surprise was that a very pale animal (that is, pink-eyed, dilute, brown; 

 genotype aappddbb) could have far more assayed oxidative enzymatic activity toward 

 added substrate than a very dark one (that is, intense black, genotype aa). (See 

 figure 47.) Our second, and most pleasant, surprise concerns the use of the thio- 

 glycolate dermal suspensions which are easily prepared. I should like to compare our 

 own data, obtained directly as readings of the Klett colorimeter scale, with those 

 computed from the histologic data of Elizabeth S. Russell. 1092, 1093 (See figure 48.) 



