Sudan III in Metabolism and Inheritance 165 



results; while at the same time we get a close view oi the sort of 

 mechanics which is back of this type of "inheritance." We may 

 state at once our belief that we are here dealing with a noteworthy, 

 though very simple, form of inheritance, but one which seems by 

 no means sufficient to illuminate hereditary processes in general. 

 By the use of Sudan the writer has been able to demonstrate 

 some hitherto unrecognized features of fat metabolism, particu- 

 larly as it occurs in birds. It seems both convenient and helpful 

 to report these results in connection with the present survey of 

 Sudan in metabolism and inheritance. 



HISTORICAL ] 



The historical background of the present studies is furnished 

 by a view of the state and source of our knowledge of the four 

 following topics: 



(i) The living membranes through which Sudan will pass, and 

 the points at which it is deposited m the body. 



(2) The mechanism of the transfer and deposition of Sudan 

 within the body. 



(3) The uses to which Sudan has been put in experimental 

 biology and medicine. 



(4) Sudan III, and other pigments, in "inheritance." 



In summarizing the data on these topics it has been considered 

 to the advantage of the reader, to include the results of the writer 

 as well as those of other investigators whose findings have been 

 published since the preliminary report of his own work. The 

 summaries, therefore, are believed to be complete to date. 



(i) Membranes Through ivhieh Sudan is Knoivn to Pass 



Intestinal mucosa: birds and mammals, (Daddi, '96). 

 Intestinal mucosa: human, (Franz and Stejskal, '02). 

 Intestinal mucosa: moths, (Sitowski, '05). 



Embryonic intestine: yolk-sac of chick, (S. H. & S. P. Gage, '08). 

 Renal epithelium: human, (Franz and Stejskal, '02). 

 Epithelium of egg chamber: moths, (Sitowski, '05). 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY. VOL. 8. NO. 2. 



