ras 
as a chemical stimulus in producing a greater number of chlorophyll 
grains by external effect, as claimed by Kumm,' or whether it is due to 
the probable combination of the copper with the cyanophyll, as claimed 
by Berlese and Sostegni,” causing a greater proportion of the latter as 
compared with the xanthopliyll, it is not intended to state; however, 
as the last-named authors have shown that a small quantity of copper 
may be absorbed by plants and find its way to the aerial parts without 
injuring them, their explanation seems more reasonable than that of the 
external chemical stimulus theory. 
PARTS OF SEED AFFECTED BY COPPER SULPHATE. 
An experiment was undertaken which was designed to show what 
part of the seed is injured by copper sulphate during the process of 
imbibition. Four lots of seed were selected so as to be as nearly uni- 
form in quality as possible, the glumes being carefully removed. The 
seeds of two lots were then cut so as to remove about one-third of the 
erain from the end opposite the embryo, leaving the starch well exposed. 
Half was soaked in water and half in a 2 per cent solution of copper 
sulphate for thirty minutes. The seed of the other two lots were 
slightly punctured with a fine needle, so that the epidermis over the 
embryo was pierced, after which they were soaked as above, and the 
four lots planted as in the other experiments. One week after planting 
the seed had germinated as follows: 
Per cent. 
Wopimendieutiot and soaked im water! .).5).2:1.os54,0-o2-5 +2 4 Seas oo 90 
Lot 2, end cut off and soaked in 2 per cent solution -....-...---.--.. 44 
Lot 3, seed punctured and soaked in water... --. Be Pee Bisa Mae pe Ue 40 
Lot 4, seed punctured and soaked in 2 per cent solution.-..-....---.. 0 
The results show that the effect is exerted almost wholly upon the 
embryo. From the low germination of lot 3 it is probable that some 
mechanical injury was done the seed whereby its vitality was impaired. 
If lots 1 and 2 are compared with the similar lot on page 18 it will be 
seen that they show nearly the same germinations, so that but little 
injury could have been done the seed by the removal of the glumes. 
It has been suggested by R. Otto® that the injury done to the embryo 
is caused by the corrosive effect of the copper sulphate acting upon it 
while the protoplasm is yet dormant, and that the living protoplasm 
will prevent the osmotic entrance of the copper to the cells, thus pre- 
venting their destruction. This presupposes the inability of copper to 
be absorbed and carried into the aerial parts of plants, a theory denied 
by many authors and shown to be fallacious by some of the foregoing 
experiments. 
1 Ber. Deut. Bot. Ges., Vol. X, No. 2, p. 79, 
*Rev. Internat. Vit. et Ginol., 1, 1894, No. 11 and 12, p. 399. 
3Naturw. Wochenschr., 1893, p. 565. 
