COPPER SPRAYS ON IRISH POTATO TUBERS. 19 
of the United States, concluded that environment rather than hered- 
ity is the major factor in determining the physical and chemical 
characteristics of the wheat crop. 
COPPER CONTENT OF VINES, STEMS, ROOTS, AND TUBERS OF SPRAYED AND UN- 
SPRAYED PLANTS. 
Copper is widely distributed in nature. Apparently all plants 
and animals contain small amounts of this metal. 
In 1816 Meissner (35) reported that copper was present in the ash 
of various plants in small quantities. Dieulafait (72) in 1880 showed 
that the amount of copper present in vegetation was largely de- 
termined by the nature of the soil. 
Lehmann (28), in 1895 and 1896, estimated the copper in wheat, 
rye, barley, oats, maize, buckwheat, potatoes, beans, linseed, apricots, 
pears, breads, cocoa, and chocolate. He found that only in the 
plants grown in soil relatively high in copper does any appreciable 
amount of copper get into the plant. The species of plant is ap- 
parently of less importance than the copper content of the soil in 
determining the amount of copper found in the plant. In wheat 
and buckwheat the copper was chiefly in_ the stems and leaves, 
little being found in the fruits and seeds. Therefore a high copper 
content in the soil does not necessarily mean that much copper is 
present in the grain and seed. The form in which the copper exists 
in plants is not known. Lehmann gives data showing that the 
quantity of copper in any species of plant varies with the individuals 
of the species, even when grown on the same soil in the same year, 
and under similar conditions. 
MacDougal (34) examined microscopically and analyzed various 
parts of a ‘tree which had grown in copper-bearing soil. He found 
metallic copper in relatively large quantities throughout the tissues, 
indicating an absorption of copper by the tree over a period of years. 
TABLE 8.—Copper in tubers from copper-sprayed and noncopper-sprayed plants. 
[ Parts per million.] 
Copper in dry tubers from vines treated with 1— 
arsenate |Bordeaux| Picker- | arsenate 
| 
Variety. | Place grown. Calcium Lead Ghee 
(no cop- | spray. jing spray-.| (no cop- per) 
; 
| 
Spalding Rose........... | gk ea 8 | in 15) Po Cee. Ree ee 
Farm, 
Trish es See ae ee ie. 3 Goeth Ms HAY ol 11 13 Oil? ae. tsp eee 2 
3 eae ae Le ee ee ats G (ener SL aes ee 11 15 DY 50 Pe ge Ye Sr ae 
Do Lt See eee ea ae 7 ee ea! GO se 5 es 14 16 Dt A) i ee eek 
worse: 05. oo) ee | oe S| maa ae Uy a 11 14 BS 'f. fete as Be ee 
TO foes 2 ee ED aisha 
American Giant.. ae eee | Nawsherseyis? 2252s Sluis oS oN wh on ees poe 10 11 
Gi bo Uy Bases oe ee 
Biaeky Orage se, Pe Pe Monnesoba 2 2eeto2' 22 ie olte ae 10} }-2 Ae eee 13 
Green Mountain .-....... Presque Isle, Me. --.-:._- EE. le BO fe 322 a A ees 9 
Magnum Bonum......... IN@W. WORK ose) oat lS | 5 SRR He LTE ea ee ee 10 
Pebble Basset... 222-222]. 22. 05 (eS gS Sa ee ae K ; : RaeaRs Aaa 2282 aes = 
ennsylyanin. 2 sees) ee [re eae fe eee 10 
Waurmouceenme ceteris ff) ipre PO ear it Roe | ERSTE MS _ 2e | 10 | RIES 10 
1 All of the copper-sprayed plants received an arsenical spray as well. 
2 Sprayed twice. 
3 Sprayed 6 times. 
