19141 
DUGGAR AND COOLEY—FILMS AND TRANSPIRATION 3 
of 1906 Stewart notes an increase in yield of 63 bushels per 
acre due to spraying five times. Не remarks: “Late blight, 
early blight, flea beetles and tip burn were all factors in this 
experiment, but none of them caused much damage." More 
striking were the results the following year when an increase in 
yield of 732 bushels per acre was obtained from spraying five 
times. In this case it is reported: Late blight and rot were 
wholly absent and early blight appeared only in traces. "There 
was some tip burn and a light attack of flea beetles. Considering 
the seemingly small amount of damage done by blight and 
insects, it is remarkable that spraying should have increased 
the yield so much." Іп 1909 the increase in yield in spraying 
six times was 492 bushels per acre, and the comment upon this 
result is as follows: * Early blight, late blight and rot were all 
absent. Some injury from flea beetles was noticeable through- 
out the season. After September 1 there was considerable 
tip burn. As late as September 24 the difference between 
sprayed and unsprayed rows appeared slight. Тһе sprayed 
rows held most of their foliage until killed by frost on October 
14." 
Тһе senior author of this report visited the experimental 
plats which afforded these data in late September, 1911, prior 
to the killing frosts of October 27, and the contrast between 
the sprayed and unsprayed rows was pronounced; at the same 
time there was very little evidence of any disease on the un- 
sprayed plats. Regarding the condition of the plants Stewart 
says: "There was no late blight whatever, only a very little 
early blight, and very little flea beetle injury. Тһе unsprayed 
rows were affected by no disease of any consequence except 
tip burn, and even of that there was only a moderate amount. 
As the plants were still partially alive twenty weeks after plant- 
ing it is clear that they could not have been very much injured 
by anything. Yet spraying increased the yield at the rate of 
93 bushels per acre. Plainly we have here a striking example 
of the beneficial influence of Bordeaux in the absence of diseases 
and insect enemies. ” 
Examining the comments of these and of other investigators 
regarding increased vitality as a result of spraying with Bor- 
deaux, we find that where the condition of the plant is well 
