A STUDY OF SWEET POTATO VARIETIES. 
19 
sufficient to alter the plasticity to any marked extent. The Southern 
Queen changed less rapidly than any of the others during curing, 
but lost its firmness rapidly in storage, arriving at the end of the 
test period in a very soft condition. Very marked changes took place 
in the Nancy Hall and the Porto Rico during the curing period. 
At the end of this time both were very soft. A continuous loss in 
the case of the Nancy Hall and a slight increase in the Porto Rico 
are noted, but they have no practical significance probably, as both 
varieties had become very soft. 
All the different potatoes studied have been found to vary in some- 
what the same way, as is shown in the examples just given. Though, 
as has been pointed out, some variations have been noted in the con- 
sistency at the time of digging, all when freshly dug yield a com- 
paratively firm product. Table 3 shows the results of consistency 
tests upon these varieties made after curing and storage. The tests 
were carried out in the same manner as in the tests just described. 
The varieties are arranged in the order of their firmness as found 
in these tests. 
"Table 3. — Relative plasticity of different varieties of sweet potatoes canned in 
the form of pie stock after curing and storage. 
Variety. 
Grams. 
Sarly Red Carolina 210 
No. 11286 172 
Big-Stem Jersey 158 
Red Jersey. ..." 137 
No. 7980..". 125 
Yellow Jersey. 10S 
Yellow St ras burg 105 
Improved Big Stem 105 
General -Grant 97 
No. 10412 • 95 
Dahomey 89 
Catawba Yellow 85 
Gold Skin 82 
Haiti 81 
No. 49711 78 
Variety. 
No. 11284 
Triumph 
No. 10650 
Pierson 
Florida 
Early Carolina.. 
Gros'Grandia.... 
Mullihan 
Red Brazil 
Red Bermuda... 
Catawba White . 
Yellow Belmont 
No. 11285 
Vineless 
No. 22437 
Grams. 
Variety. 
Grams. 
No. 39833 
42 
Kev West 
35 
Miles 
34 
34 
30 
Ballinger's Pride 
30 
29 
29 
Creola 
28 
Porto Rico 
28 
Vineless Pumpkin 
"Yam" 
Nancy Hall 
25 
20 
It will be seen that after curing and storage the plasticity varies 
all the way from quite firm to very soft, all degrees of plasticity being 
found. 
These observed changes in consistency during curing and storage at 
once raised the question as to the cause, and the samples were sub- 
mitted to chemical analysis to determine what substances were in- 
volved. The analyses were carried out in the following way : Dupli- 
cate samples of 100 grams were weighed out from the thoroughly 
mixed material and enough 95 per cent alcohol added to give an 80 
per cent mixture. This was thoroughly stirred, and after standing 
for several hours the alcohol was decanted through an extraction cup 
into a flask and more 95 per cent alcohol added to the material. This 
was repeated three or four times. After decanting for the last time 
