90 
RECENT EXPERIMENTS BY DR. MINK8. 
Cohn, Caspary, and J. Muller, and we find nine authors who com- 
pletely reject the theory. In the front rank of these we must 
place Mr. Crombie, then Messrs, de Krempelhuber, Th. Fries, W. 
Nylander, Franck, Caruel, Koerber, Archangeli and Weddel. 
The learned world is at the present moment discussing two works 
on this algolichenic question, which are as yet but little known. 
The earlier in date is that of Dr. Sthal, “ Culture complete jnsqu 
a la fructificatior although interpreted favourably to M. Schwen- 
dener’s theory, this work is not devoid of interest, but it is im- 
possible to avoid recognising by the very results of the culture, as 
reported by the author — notably apropos of a little Pyrenocarp 
( Thelidium minutulum ) — that the algolichenic theory has had its 
day. 
Dr. Sthal is in contradiction to M. Schwendener, since the latter 
asserts that the captive algae are compelled to produce nourish- 
ment for themselves and their sovereign (fungo-lichen), while Dr. 
Sthal, on the other hand, has perceived that the hymenial gonidia 
take their nutriment from the constituent parts of the liymenium 
which surround them ; and he even adds that the gonidia owe their 
greater dimensions to the influence of the Ascomycetes. Would 
not this contradiction suffice to cause the recognition of the falsity 
of the proposed system ? 
The observations based on the cultivation of the spores of The- 
lidium minutulum , with the spores of Endocarpon pusillum , are 
valueless. 
If the author had cultivated the spores separately, he would 
have observed the same phenomena, but he thought this was un- 
necessary, since he began by that which he wished to prove — the 
singular genesis of the gonidia. 
The labours of Dr. Minks are of very great importance, for they 
definitely decide the algolichenic question, while, at the same time 
profoundly modifying the anatomical notions which were enter- 
tained concerning the thallus of lichens. In his Memoir entitled, 
“ Culture et vie des Lichens,” this clever observer treated especially 
of the origin and development of the gonidia — an important point 
which is neglected by the schools of Messrs. Schwendener-Bornet. 
In his recent publication (“ Flora,” 1878), Dr. Minks not only 
confirms M. Tulasne’s theory, establishing the fact that the gonidia 
decidedly have their origin in the hypha and cortical cells, but he 
proves from his experiments — experiments which have already been 
checked by other Cryptogamists, and principally by Dr. Muller, 
(Professor at the University of Geneva) — that the microgonidia, 
which are transformed into gonidia, exist in the hypha, rhizines, 
cortical cells, paraphyses, young thecae, and even in the spores and 
spermatia — that is to say, in all the vegetative and reproductive 
cells. The transformation of the microgonidia into gonidia can 
easily be seen under the thin cortical layer, and in those parts of 
the bark which are contiguous to the medulla. 
The Rev. J. Crombie, one of the most energetic, and also one 
