338 



BIOCHEMICAL GENETICS 



Except for possible differences of scale (Dr. Russell's scale, using an arbitrary unit 

 called pigment volume, is based on the number and average dimensions of melanin 

 granules at a given developmental stage), there is a very striking and gratifying paral- 



Fie 48 Comparison of turbidimetric estimates of natural melanin content ("un- 



* *&* * w * , 1flQ9 10Q3 



incubated" subsamples) with estimates based on E. S. RUSSELL S HISTOLOGIC DATA 1 I 



("pigment volume"). 



260 



240 



220 

 </> 

 2 200 



j: i8o 



LU 



* 160 



S 140 



< 



m 



=> 120 

 o 



z 



§■ 100 



80 



900 



- 800 _ 

 to 



H 



§ 700 



>- 



< 600 



CC 



K 



cd 500 



cc 

 < 



400 



LlI 



2 



3 300 



> 



i- 200 



z 



111 



§ 100 



4th -30th FIELDS 



DATA FROM 

 ES. RUSSELL, 1946,1948 



_ 4th -20th 

 FIELDS 



lelism as to order of effect, with respect to natural melanin content (subsamples not 

 incubated), as a function of genotype. This parallelism gives us a reasonable measure 

 of confidence in the use of the thioglycolate suspensions for obtaining measurements of 



