157 
which had reached a size of about 5 to G inches, were thus infected. 
Where the germs touched, a local sickening was visible after 4 to G 
days. This took the form of a yellowing and subsequent shriveling of 
the leaves. These were covered with penetration spots, and penetrated 
in all parts by richly branched fungous threads. The leaves died, but 
neither completely nor with the formation of smut in their interior. As 
soon as the plants were compensated by new sound leaves from the bud, 
they appeared healthy again; but were, of course, somewhat delayed 
in their development in proportion to the disturbance. Moreover, this 
whole series of plants proved sound, and brought forth healthy panicles. 
IX. An additional 210 millet plants, about a a foot high, were infected 
in the heart from above. Here the effect was still more remarkable. 
The young leaves which had been touched and attacked, shriveled con¬ 
siderably after a week, the heart of the plant became very pale, and the 
mycelium grew luxuriantly through all the attacked leaves. Neverthe¬ 
less, even here, the diseased leaves were subsequently replaced by sound 
ones, and aside from the delay in development the plants suffered no 
injury. The subsequent harvest yielded only sound panicles. 
X. Again, 120 plants, 1J to 2 feet high, were infected in the same way. 
The symptoms on the attacked leaves grew worse in proportion to the 
increased size of the vegetative point, so that from external appear¬ 
ances it seemed as if the plants would perish ; but this did not happen, 
and again the new leaves were sound. The result in autumn was the 
same as before, only sound plants. 
The panicle can not be reached by infection from above in millet any 
more than in oats. It is securely inclosed by the leaves of the bud, and 
subsequently pushes out sidewise from these. For this reason, addi¬ 
tional infections, when the plants were 3 to 4 feet high, had a purely 
negative result. The young leaves were luxuriantly traversed by the 
penetrated germs, but the panicles remained uninjured. 
The final result of the experiments with millet smut on the sugar 
millet [sorghum] points to the following conclusions: The plants can 
be infected with the smut germs in all young undeveloped parts; but 
only those smut germs which have penetrated into the nascent shoot, 
and have thus reached the growing point, actually produce smut in the 
panicles, which is its exclusive location. These fungous germs, which 
have penetrated the host plant in the first stage of germination, re¬ 
main, as in oats, latent in the plants till their sexual maturity, and then 
only do they come to maturity in the young ovaries, and to the produc¬ 
tion of smut beds, which is equivalent to 'the destruction of the ovaries 
or of the panicle. 
It is worthy of remark that we can not discover the least sign of dis¬ 
ease in the plants which bear the destructive germ concealed in their 
growing points ; that, on the contrary, they appear even more luxuriant 
than the others; and furthermore, that the smutty panicles appear 
much sooner than the sound ones. For example, in the third series of 
experiments. 102 smutty panicles had developed up to September 3, 
