Gelehrte Gesellschaften. 
431 
ferous masses had been protruced by rains, and kept apart in water 
for the subsequent sowings. 
The method of infection was as follows. Unexpanded spori- 
ferous masses were put in watch-glasses with a little water, and these 
placed in a moist chamber, a common jelly tumbler filled with wet 
sphagnum being found convenient for Ibis purpose. In from twelve 
to eighteeu hours the teleutospores had as a rule produced an abun- 
dance of sporidia in the water and on the surface of the expanded 
masses. The latter were then torn apart, and placed directly upon 
the plants to be infected, which were first thoroughly sprinkled , and 
after infection kept, when practicable, under bell jars or cones of wet 
paper for about twenty-four hours; after which they were uncovered 
and repeatedly sprinkled. The results obtained seemed better where 
portions of the jelly were applied, than when water with sporidia 
in Suspension was employed; but in the former case it is necessary 
to remove the dried membrane that remains, which otherwise injures 
the tender leaves. 
In view of the theory that the spermatia are sexual in function, 
and fertilize a female organ, the trichogyne, which subsequently 
gives rise to the aecidium, a „fertilization“ was attempted by collecting 
the exudations from the spermogonia in a drop of water, and paint- 
ing them upon the under side of different leaves in plants infected 
by the same species. This was carefully followed up with G. g 1 o - 
bosum, without resulting in the production of auy aecidia, and in 
two instances where aecidia were obtained (G. biseptatum and 
macropus) no such fertilization was attempted, thus giving no de- 
finite result for or agaiust the sexual theory. It should be mentioned 
that small flies were repeatedly observed feeding on the secretions 
of the spermogonia; yet as these are usually confiued to the upper 
surface of the leaves, it is difficult to understand the agency of 
such insects in fertilizing a female organ borue supposedly on the 
under side. 
Turning now to the individual cultures my results with the dif- 
ferent species were as follows. 
G. macropus. 
April 30. Sporidia sown on 
3 Pyruä America na. 
4 Pyrus malus. 
3 Crataegus coccinea. 
May 11. No result. All the plants reinfected, and in addition 
2 Amelanchier Canadensis. 
1 Pyrus arbutifolia. 
May 13. Spots with spermogonia appeared on single leaves of two 
apples ; but being questionable, the leaves were cut off. 
May 22. Spermogonia appeared abundantly on two apples. 
May 28. Two additional plants of Pyrus malus infected, on which 
spermogonia appeared. 
June 5. Sporidia sown on immnture fruit of Amelanchier, which 
was kept under a bell glass. 
June 12. Signs of aecidia forming on the under side of the apple 
