554 
PROFESSOR H. MARSHALL WARD OR THE 
the cell-walls required some evidence. Anyone who has worked with such mycelia as 
those of the Ustilaginese must have seen hyphae as bright and delicate as these. 
The point as to the budding of the gemmules from the hyphae is a more difficult 
one, because it seems impossible to witness the process of budding off itself. The view 
proposed by Brunchorst, and accepted by Tschirch, that the gemmules (“ bacteroids”) 
are remnants of a broken-up protoplasmic network, is quite untenable in the cases 
examined, and Tschirch gives no figures illustrating such a process. I have shown 
that the gemmules arise in connection with the hyphae in the cells, and not as points 
scattered in a matrix. Brunchorst himself seems to have held at one time the idea 
that these “ bacteroids ” escape from the interior of the hyphae like minute sporules, 
but the account is by no means clear. It seems impossible to explain the frequent 
cases shown in my figures 15, 16, and 17 on any other view than that they are the 
gemmules budding off from the hyphae, and it ought to be noticed that others have 
seen similar cases, but without properly explaining them. For instance, Tschirch 
himself says (p. 76), “ In einem Falle nur schien der Kopf eines Fadens mit unzahligen 
behauften runcllichen Ausstiilpungen besetzt,” and in a foot-note he remarks, “ Diese 
Bildung ist vielleicht mit der von Prillieux beschriebenen Auflosung der Faden der 
warzigen Massen identisch ” (p. 76).'" Again, it is difficult to attach any other meaning 
to Frank’s figures (‘ Botan. Zeitung,’ 1879, Plate V., esp. fig. 11) than the one he 
then ascribed to them, though he has since retracted his explanation in a most 
unaccountable way—erroneously, I am convinced. 
It is still more difficult to accept Tschirch’s assumptions as to the “ bacteroids ” 
(gemmules) themselves. It may be true that their variable shapes militate against 
their being bacteria, but bacteria are not the only alternative, as he assumes, and 
these very shapes are fully in accordance with their being gemmules—tiny, yeast-like, 
budding organisms—as a comparison of Frank’s figures and my own with those of 
Tschircii’s amply testify. Tschirch’s assumption that the filaments (hyphae) dissolve, 
and the protoplasm then breaks up into “bacteroids,” is certainly not true for the 
tubercles of Vicki Faba. In fact, the whole of this purely hypothetical explanation of 
the nature of these bodies is contradicted by the facts observed in Vida Faba; whereas 
tire phenomena are simply and naturally explained when we recognise that the hyphae 
bud off the gemmules, which then multiply further by budding like tiny yeast-cells. 
These then pass into a dormant state in the matrix, and escape into the surrounding 
soil when the tubercles decompose at the end of the season of growth, and are there 
distributed in readiness for contact with root-hairs of other seedlings in the following 
O O 
season. 
It now remains to examine the rest of Tschirch’s paper. He expressly states, 
and repeats, that water-cultures are useless in the investigation, though no satis¬ 
factory reasons whatever are given in support of this view. He admits that the 
* Prillieux (‘ Bull. Soc. Botau. de France,’ 1879, p. 98) regards the cause of the tubercles as a 
plasmodium. 
