134 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN’S COMPANION, June 2, 1857. 
the season, when nay attention was more particularly called 
to the subject by a communication from the Irish Commis¬ 
sioners, I did not succeed in 1845 in making the spores 
germinate, though M. Decaisne informs me that he found 
no difficulty in doing so. They germinated, however, leadily 
enough in the summer of 1840. My attention, indeed, was 
turned more particularly to the point at an earlier portion o 
the year, when it was difficult to get more than one or two 
infected leaves, and even had it been possible to collect the 
spores in any quantity, experiments seemed more likely to 
give a speedy result if directed to some cereal parasite, such 
as bunt. The spores are of a peculiar structure, of sufficient 
magnitude be easily observed, and the mycelium produced 
of considerable size, and as the disease was to be developed, 
ultimately in a particular organ, to the production of which 
the ultimate energies of the plant were directed, there seemed 
a good chance of being able to observe the progress of the 
mycelium. I hoped then to ascertain whether the actual 
penetration of the mycelium into or amongst the tissues of 
the plant were necessary, or whether the grumous contents 
of the spores, if circulated amongst the juices, might not be 
sufficient for its propagation. The latter notion had been 
lately advanced as a mere theory by Dr. Greville, and I felt 
inclined to believe, from various observations and considera¬ 
tions, that there was some probability at least about it. The 
importance of obtaining, if possible, correct information on 
the point is at once obvious. 
Having determined then to direct my attention to bunt 
especially, I procured as good a sample of wheat as possible, 
and divided it into two portions, washing the one carefully, 
and then sowing it with every precaution, that there should 
be no contact with any of the spores of the bunt with which 
I was experimenting; the other portion was steeped in a 
thick mixture of bunt and water, a portion of the black 
liquor being poured on the surface of the soil after the 
impregnated grains were sowed; the progress of the grains 
and spores was thep daily examined. The clean wheat 
sprang up as usual, but there was soon an evident difference 
in the infected grains, a difference which was distinctly 
visible till the ears were perfectly developed, when every 
infected plant was bunted, while from the unimpregnated 
seeds not a single bunted ear was produced. In one of the 
bunted plants not only the ear was diseased, but there was a 
streak of bunt upon the stem, in which the fetid smell and 
peculiar structure were not to be mistaken, a circumstance 
whicli I have never before observed, nor am I aware that 
the fact has been noticed by others, and confirmatory of the 
opinion that the disease is not a mere alteration of structure 
in the grains of fecula, were such testimony wanted. 
Four days after sowing I found that the spores of the 
Uredo had been sucked in, doubtless by capillary attraction, 
between the young root and its investing membrane, which 
was ruptured, germination at that period having scarcely 
taken place. The spores were quite as large as either of 
the two distinct series of cells of which the young root is 
composed. 
Three days later I perceived the first traces of germination 
in the spores. A little obtuse tube thicker tha,n the pellucid 
border of the spores, in a very few instances only, and 
appearing like a short peduncle, scarcely so long as their 
diameter, was protruded through the external membrane. 
This surprised me extremely, because on the mass of spores, 
whether on the surface of the soil or on the grains of wheat, 
there was a white, very delicate, extremely short down. On 
a closer examination the greater part of the grains of bunt 
were found to be clothed on one side with fascicles of white 
filaments, from two to four times longer than the diameter 
of the bunt spores, and producing towards their apices 
extremely long and slender, somewhat curved acuminate 
multiseptate spores. 
Three days later a large portion of the grains of bunt 
were ruptured, either irregularly or in a stellate form ; a few 
more had germinated, the filaments being evidently pro¬ 
truded from the internal membrane, and either straight or 
curved, and occasionally branching off in two opposite direc¬ 
tions, the tips of the threads being in all cases very obtuse, 
and many times larger than the intercellular cavities of the 
tissue of the roots. » 
I he parasite, meanwhile, had undergone a very curious 
change, the spores being no longer separate, but connected 
with one another by one or more short transverse tubes, 
exactly as in the threads of Zygnema. 
Two days later many more of the bunt-spores were rup¬ 
tured and the mycelium more elongated; and, after three 
more 5 days, the parasite was vanishing, and scarcely visible 
any more en masse to the naked eye, while the mycelium 
had increased to the length of six or more diameters of the 
spores. The young infected wheat plants were now evi¬ 
dently diseased, the sheaths and base of the leaves looking 
crumpled, and spotted either with white or brownish specks, 
and the whole appearance less healthy than that of the 
unimpregnated plants. . 
The diseased sheaths were now, in most cases, lull of 
mycelium, but no such appearance was visible in the healthy 
state. Though the disease had evidently commenced, it is 
to be observed that the tubes protruded by the spores were 
but slightly developed, and that, though the utmost pains 
were taken, I could trace no connection whatever between 
Tissue of diseased sheaths traversed by mycelium 15 days after inoculation. 
these and the diseased tissue. There was not the slightest 
doubt as to the fact that the two sets of wheat plants exhi¬ 
bited quite a different appearance; and my own observations 
were confirmed by several practical men who saw them. It 
is of course incapable of proof without tracing the connection 
of the internal mycelium with that produced by the spores, 
that the two were really derived from the same origin; but 
as the peculiar appearance was exhibited only by the impreg¬ 
nated plants there is a strong presumption as to identity. 
All the plants were afterwards more or less infected with 
U. Rubigo vera , which appears to be the infant state of 
Puccinia graminis, and which afterwards was developed, and 
there would of course then be matter of doubt to what 
fungus any observed mycelium might belong. 
In a single instance only, ten days after the first appear¬ 
ance of disease, in examining some little white specks which 
appeared on the leaves of the bunted wheat, I saw a curved 
filament passing through one of the stomata, but whether 
from the outside to the inside, or the contrary, I cannot say. 
The mycelium in these white specks was not abundant, but 
thicker than the walls of the cells. 
In a month from the sowing of the wheat, the fecula of the 
grains being then nearly absorbed, it was difjdcult to find any 
spores, and no further development of mycelium, directly 
from the spores, had taken place. 
The first bunted ear appeared four months from the time 
of sowing, and while every impregnated plant produced 
bunted ears, not a bunted grain appeared on the plants 
which sprang from uninfected seed. 
The experiments were repeated with precisely the same 
