240 Dry Matter and Nitrogen, in the Potato Tuber 



This misled East into assuming a correspondence between the cortical 

 layer of Coudon and Bussard and the inner skin of Frisby and Bryant. 

 The former constitutes about 35 per cent, of the whole and the latter 

 only 8-5 per cent. 



Frisby and Bryant throw Ught on the somewhat surprising result 

 of Coudon and Bussard's work, that the apparently dry skin contains 

 less dry matter than the obviously wet flesh of the tuber. It appears 

 that there is a very wet layer, the inner skin immediately below the dry 

 outer cuticle. This, which wholly or partially is generally removed with 

 the outer skin, gives the low figure for its percentage dry matter. When 

 taken together inner and outer skin contain a smaller proportion of dry 

 matter than the flesh while each layer contains a higher percentage of 

 nitrogen. These results agree mth those obtained by Coudon and 

 Bussard. 



Further investigations were published by Waterstradt and Willner(5) 

 in 1901. They divided the tuber into cortical and medullary areas, but 

 did not separate the external and internal medullary. The average 

 results for three varieties of good table quality and for three coarse 

 starch producing varieties, both types grown on two separate fields, 

 are shown in Table III. 



