40 Ward —Recent Researches on the Parasitism of Fungi . 
the light and air of the Eastern greenhouse. Not only did we trace 
starvation effects on the hyphae, but in the heated pots we found corroded 
nests of cells as in the immune plants. Since our work is not yet finished, 
however — we have yet to examine thousands of sections of these leaves — 
I defer discussion of the details for further communications. 
There is one other series of experiments to which I must refer, 
however. 
We have been much occupied with infections on leaves deprived of 
carbohydrates by keeping them in the dark, or in light from which the red- 
orange end is filtered off, &c. But especially important are the attempts to 
grow the Fungus in leaves from which all atmospheric carbon dioxide is cut 
off by potash, but which are normally supplied with water and light, and in 
some of the experiments with minerals in normal culture solutions. 
I select one series for illustration. 
Experiment 15. 
On May 18 three pots were prepared, and in each were sown 
fourteen grains of Michigan Bronze, a variety selected because it was 
known to be very susceptible to Puccinia glumarum , and was used by 
Eriksson. 
On June 15 the plants were strong and vigorous, each showing the 
fourth leaf. On June 15, 5 p m., uredospores obtained from Michigan 
Bronze were sown on eleven of the first leaves, all over the upper surface, 
and the inoculated plants were placed under damp bell-jars. The whole 
growth, and subsequent operations, took place in the Eastern greenhouse. 
The inoculated plants were then left for twenty-four hours, to initiate 
infection ; and at 5 p.m. on June 16 were treated as follows : — 
Six of the inoculated leaves were cut off close to the base, and each 
placed in a separate tower-tube, the tubes labelled A, B, to F. The base 
of this tube contained distilled water, over which was a light plug of wet 
cotton-wool, on which the cut surface of the leaf rested. Into this basal 
water plunges the exit end of a tube which carries the air to be drawn 
through the tower, which air, after passing over the leaf, escapes at 
the top of the tube. 
The tower-tube described above is linked up to a second tower, 
arranged in exactly the same manner, except that it contains no leaf on a 
cotton-wool plug, but merely acts as a receptacle of water to wash the air 
coming through the tube. 
This latter is linked to a triad of bulbs charged with a strong solution 
of potassium hydrate, the proximal end of which is open to the air. In 
some cases Pettenkofer tubes were employed. 
Of the six leaves selected, four were placed as above in tubes thus 
