On WJieat Mildew. 
495 
force may be demonstrated. What is its cleansing power on 
the milk ? What the effect of working upon milk rendered 
more dense by the addition of sugar or salt ? What is its effect 
on the fats, as influencing butter-making and butter-keeping ? 
What change, if any, does it produce on the skim-milk? Can 
this force be used in cheese-making for the separation of the 
curd as coagulated ? Can adulteration be detected by its aid ? 
And so we might continue ; but until experiments are carefully 
made, such conjecturing must belong to the] region of fancy 
rather than to that of reality. 
XXVI.— On Wheat Mildew. By WiLLiAM Cakrutheks, F.R.S., 
Consulting Botanist to the Society. 
The minute fungi which live on other plants and produce 
blights or diseases, have received special attention in recent 
years, because of the serious losses which they bring with them, 
and because of the remarkable facts in the economy of vegetable 
life which their study has disclosed. 
The hop, the vine, the potato, and the different cereal crops 
are equally liable to great injury, and sometimes to destruc- 
tion, from the attacks of these parasitic plants. And none is 
more wide-spreading in its attack, and more serious in its 
action, than the mildew which, attacks the wheat-crop in 
summer or autumn. 
The desire to discover some means of preventing or alle- 
viating the malady caused by mildew, has led to the frequent 
careful study of this plant. In the second volume of this Journal 
(pp. 11 and 220), Professor Henslow, in a paper on the diseases 
of wheat, gave a careful description of the mildew, and reasons 
for believing that rust and mildew were produced by the same 
fungus. He also investigated the prevalent notion that the 
barberry was in some way connected with the mildew, and 
recommended that experiments should be instituted with the 
view of testing the matter. He was not himself prepared to 
accept the opinion, though he records a case which he found it 
hard by any other explanation to understand. A farmer in 
Oxfordshire had a field which, when sown with wheat, was gene- 
rally infected at one portion with mildew. This part was in 
the immediate neighbourhood of an old hedge, in which there 
were several barberry bushes. The blight did not extend 
farther than twenty yards from the hedge, and it was most 
abundant in the immediate neighbourhood of each of the some- 
what widely separated bushes. The farmer had all the barberry 
