40 THE MICROSCOPICAL NEWS. 
been asserted that the existence of a genetic relationship between 
the gonidia and the hyphz has never been proved—in fact that 
there is none, and that the gonidial elements may all be referred to 
some well-known group in the A/ge. Rees has attempted to form 
a Lichen by synthesis from the distinct algal and fungoid elements, 
and his experiments, though not absolutely successful, have yielded 
results which he can only explain by taking the dual nature of 
Lichens for granted. Again, Stahl, in 1877, succeeded in producing 
a Lichen from the spores and hymenial gonidia of Exdocarpon 
pusillum, which developed perithecia and spermogonia. It has 
also been found that the same Lichen thallus may contain widely 
differing species of A/ge associated together, while on the other 
hand the same A/ga may occur in perfectly distinct Lichens. These 
facts, and others which we have not space to mention, undoubtedly 
help to make a strong case for the theory, but its opponents are 
many in number, and they have very weighty arguments to bring 
forward against it. Dr. Minks seems to have proved conclusively 
that there zs a genetic relationship between the gonidia and the 
hyphe, as he has detected in all the parts of the latter certain small 
bodies which he calls mécrogonidia, some of which develope a 
membrane and eventually become true gonidia. 
These results of Dr. Minks have been strikingly confirmed by 
Dr. J. Muller, of Geneva. ‘This gentleman recently found a speci- 
men of Canogontum pannosum in which one of the large filaments 
bearing the gonidia suddenly narrowed into the ordinary hyphal 
filament, and in this latter he was able to clearly distinguish micro- 
gonidia—gonidia in embryo. If the Schwendenerian hypothesis 
were correct, the broad part of this tube should be in A/ga, and the 
narrower part in /ungus; but Dr. Muller, regarding this as an 
absurdity, views them as different stages in the evolution of one 
and the same individual. Nylander has remarked, too, that the 
gonidia are essential to, and take an active part in, the life of the 
Lichen, which does not authorise us in considering it merely as the 
host of a parasitic fungus ; and, moreover, the size of the host would 
be so disproportionate to that of the parasite, that, as Cooke says, 
it would be a case of an elephant parasitic upon a flea. In all 
other cases of parasitism the host is destroyed to provide for the 
support of his guest ; but here, it is affirmed, we have an exception, 
and the Alga, so far from suffering, receives an increase of strength 
and vitality from the draining of its juices by the fungus. 
Then, again, if the theory holds good we must assume that the 
Fungus has very abnormal powers and properties conferred upon it 
by its singular mode of living. Thus Discomycetous Fungi are 
annual and short-lived; Lichens are perennial and attain a great 
age. Fungi prefer moisture and thrive best in the dark ; whereas 
Lichens will flourish in the most open and arid situations. Their 
