232 The American Naturalist. [Mareh, 
The spread of the disease is greatly facilitated by the method of 
growing the seedlings (“bibit”). Several beds are prepared one after 
another, so that the series contains seedlings of all ages. These are 
separated by narrow walks, and are themselves narrow enough to permit 
the coolie to reach all parts of the bed. 
In his search for worms or insects the coolie touches diseased and 
healthy plants, transferring the fungus from one to the other. He also 
carries the germs about on his clothing or tools and watering pot. 
The mature plants often show the disease on the tips of the leaves, 
where persons have brushed against them in passing. The parasite also 
spreads over the ground, growing from bed to bed across the narrow 
walks. i 
In one case only was the agency of wind as good as proven. In this 
case the center of infection lay to the windward of the later attacked 
beds, and the beds not in the path of the wind were not attacked. 
Conidia are produced in abundance. The conidiophores usually pass 
out through the stomata, but may push up through the epidermis. At 
the end a pear-shaped (ob-pyriform as shown in the figures) conidium, 
86 x 25 mic. mil. in size is formed, and when ripe is cut off from the 
conidiophore by a cross wall. 
A second conidium is sometimes developed from the side of the first 
one, and remains connected to it by a short hypha. The contents of 
the first conidium pass into the second one, in which the swarm spores 
are developed. The development of the swarm spores requires about 
20-30 minutes, at the end of which time the “slime plug” at the apex 
of the conidium dissolves and they emerge. The number observed in 
a conidium varied from 10 to 15. 
Each swarm spore has one flagellum, and may have another, but of 
this the author is uncertain. The swarm spores may give rise to sec- 
ondary conidia. Two cases were observed, but in neither case was the 
development of swarm spores seen. In the first case the conidium was 
developed three days after the liberation of the swarm spore in a hang- 
ing drop water culture. It remained in the same condition a few days 
and then perished. In the second case the conidium was found open 
at the end of four days and the contents gone. No mention 1s made 
of swarm spores in the surrounding medium. pea 
Sexual reproduction takes place by means of oogonia and antheridia. 
The antheridium may arise from the same hypha as that on which the 
oogonium is borne, or on a different one. The contents of the anther- 
dium are emptied into the oogonium, after which the oospore RE a 
wall about itself. The process is in all respects the same as that in othe 
