ON THE ANGUILLULIDÆ. 87 
rather than vital, and due to the rapid imbibition of water by the previously dried 
animal. 
With respect to the Vibrio tritici, I may state that this year I succeeded in infeeting 
some wheat with young specimens taken from a gall several years old. As my stock was 
small, the method followed was that adopted by Bauer—that is to say, the placing some of 
the young Nematodes within the cleft of the seed, allowing them to dry in this situation, 
and then consigning the seeds to the earth in the ordinary way. This was done in the 
end of February last, when eighty seeds so infected were sown in a box containing 
ordinary soil; and on the 8th of July I discovered one plant evidently diseased. It was 
extremely stunted, being only about five inches in height; and the whole speeimen was 
dry and withered, with the exception of the small and abortive ear. This contained no 
healthy florets, the diseased ones being about fourteen in number, each being composed 
of the slightly altered glumes and paleæ surrounding a gall of the usual size and ovoidal 
shape, instead of a germen. In confirmation of this view of the gall-like nature of the 
growth, as ascertained by Davaine', I may state that at the time when these bodies had 
attained their full size and maturity, the other healthy plants were only just flowering, 
the germens in them being minute and undeveloped. T am also able to testify to the 
probability of the correctness of Davaine's description of the precise method in which the 
disease is produced, and the young worms come in contact with the growing flower. 
Before his time the only observers who had attempted to explain the manner in whieh 
the young Vibrios reach the ear were Roffredi? and Bauer; and both these investi- 
gators imagined the little Nematodes obtained an entry to the vessels of the plant, and 
were so transmitted to the germen. Bauer, indeed, whose paper, apart from the special 
subject on which he wrote—namely, the degree of vitality of these animals—is full of 
inaccuracies, and whose figure and description of the adult animal is utterly unlike the 
original, imagined that the young, found in what he considered to be the diseased grain, 
were the products of a third generation in this spot, the two others having taken place 
within the vessels of the stem of the plant during the progress of the animals towards the 
flower. But the real process, according to Davaine, seems to be this :—When the infected 
galls are sown together with healthy seeds”, the young in a week or so, according to the 
degree of moisture of the soil, make their way out of the softened gall, and, diffusing 
themselves in all directions, some come at last into contact with the budding plant just 
' Davaine has occasionally found a small abortive germen within the same floral envelopes with the gall; and in 
this case the gall is most likely to have been produced in one of the rudimentary scales, which would have gone to 
form a stamen. He believes it may be formed out of any of the scales belonging to the central parts of the flower ;, 
and although, as a rule, all these parts participate in the formation of a single central gall, still occasionally as many 
" three growths of this kind develope within the same pair of glumelle. On one occasion he found a growth of a 
er nature, aud with the same kind of contents, growing from one of the leaves of the wheat. After this, addi- 
tional proof as to the nature of the growth is almost superfluous. All interested in this remarkable disease of wheat 
s cnl M. Davaine's admirable memoir on the subject. | 
i bservations sur la Physique, t. v. p. l, 1775. 
That the disease may be produced artificially, by placing the young within the cleft of a healthy seed, after the 
method of Bauer, I can have little doubt, after the result of my own experiment, though Davaine seems to be rather 
incredulous concerning this mode of its production (Joc. cit. p. 16). 
