TUBERCULAR SWELLINGS ON THE ROOTS OF VICIA FABA. 
547 
The next question is, what are these bacteriam-like corpuscles, or granules, and how 
do they arise and thus crowd the protoplasm ? They seem to be budded off from the 
projections of the hypha in the cells : although I have failed to see an undoubted 
case of the actual formation and separation of one of these minute corpuscles, still 
there is not much room for any other view of their origin in the face of preparations 
such as yielded figs. 12, 15, 16, and 17. These extremely minute bodies are, according 
to my view, budded off in large quantities from the hypha.* They then multiply 
further by budding in the cells. This explains their shapes, which are Y and V-shaped, 
or branched still more, in the younger states, but more uniformly ellipsoidal when 
older, and also accounts for their rapid increase in numbers. 
The bacteriumdike corpuscles are thus to be looked upon as extremely minute, 
elongated, yeast-like cells or gemmules, and it is not difficult to suppose that their 
sudden and rapid increase in the juices of the cell would give rise to the vacuolation 
of the protoplasm. It seems impossible to doubt that the so-called plasmodium seen 
by various observers in these tubercles is really the protoplasm of the cells themselves, 
stimulated into increased activity by these parasitic gemmules .t In any case this seems 
a fair explanation of the fact that the protoplasm of the cell becomes exceptionally 
frothy and vacuolated, and the cell itself enlarges quickly, coincidently with the 
appearance and rapid increase of the tiny gemmules. At this time, also, vigorous 
specimens have these cells abundantly supplied with starch at the period when the 
above increase in size and coincident multiplication of gemmules occur (fig. 12). The 
only explanation seems to be that the parasitic gemmules and hyphse are stimulating 
the protoplasm to greater activity, and thus making the cell act as a centre of attrac¬ 
tion for the plentiful supplies of carbo-hydrates sent down from the leaves, and other 
substances coming up from the root-hairs. 
Tracing the hyphse from the cortex into the young tubercle, then, and the changes 
which go on in the cells of the latter, the following facts are to be noted. The single 
stout hypha (fig. 9 a) first breaks up into numerous branches (figs. 8-12) which 
distribute themselves in all the cells of the dividing mass of tissue—the incipient 
tubercle. While the younger branches continue this process the older ones form the 
short branches, and begin to bud off numerous tiny gemmules into the cell-contents 
(figs. 12-17) : the struggle between the protoplasm and these gemmules—which 
themselves go on budding—is evinced by the frothing and activity of the protoplasm, 
which thus comes to resemble a plasmodium, and by the accumulation of starch, and 
perhaps other substances also. This causes the cells to grow (hypertrophy), and by 
the time the hypertrophy has ceased the gemmules in that particular cell have ceased 
* Frank was also inclined to the same view (‘Botan. Zeitung,’ 1879, p. 385), but he has since 
retracted his opinions on the whole subject in a most unaccountable manner. See ‘ Berichte d. Deutschen 
Botan. Gesellscliaft,’ 1887, pp. 56 and 57. 
t In order to avoid the inference that I suppose these cells to be true Saccharomycetes, they may be 
conveniently termed gemmules. 
4 A 2 
