THE DUAL LICHEN HYPOTHESIS. 
125 
Truly we may say — 
“ Science has bubbles, as the water hath, 
And these are of them.” 
Despite the announcement of the President of the Royal Society, 
for whom personally no one has a greater esteem than myself ; 
despite the flourish in the pages of the ‘‘ Nineteenth Century,” I 
not only dare to call in question, as vigorously as I can, the sound- 
ness of this doomed hypothesis, but to prognosticate its dissolution. 
Doomed, I say, advisedly, because, being illogical and unsound, it 
must, sooner or later, the sooner the better, go “ into liquidation.” 
It is worthy of note how conclusions are assumed without exami- 
nation or enquiry, but entirely, as one might say, developed out of 
inner consciousness. Thus in the “ Gardener’s Chronicle” (Feb. 
1, 1879, p. 146), it is said : “Some of Reinsch’s observations 
include some curious instances of one alga parasitical in the thallus 
of another, thus strengthening the algo-lichen theory of Schwen- 
dener and others.” Now this is a logical fallacy. Parasitism is, 
probably, not at all uncommon in Algas. It is very possible that 
the fact is true, but how does it follow from the premises that this 
conclusion is to be arrived at? 
I. — One alga may be parasitic in the thallus of another. 
II. — A fungus is parasitic on an alga in Lichens. 
III. — Therefore the fungus is an Alga. Is this the argument ? ' 
or what is it? because it is not affirmed that an Alga is parasitic in 
the thallus of a lichen, but that the Alga is the host. Some things 
seem to have got a little mixed somewhere when the above para- 
graph was written. I have not appealed to authorities, or mar- 
shalled the names of those who refuse to be parties to the “ scare,” 
because of the weakness of such a course of argument ; but, as I 
draw to a close, I may justify my position by again enquiring how 
it is that this hypothesis is not accepted either by the lichenologists 
or the mycologists. Why are its strongest advocates and most 
persistent supporters those who, from their own writings, give 
evidence that they have but an exceedingly small practical 
acquaintance with either lichens or fungi ? The whole contro- 
versy, in so far as its advocacy is concerned, teems with errors 
such as practical lichenologists and mycologists could not have 
made. There can be no truer test of a man’s knowledge than to 
permit him to write away at his own sweet will. Believe me, it is 
not by any means difficult to determine the shallowness of a man’s 
knowledge, if he is only permitted to write and talk as he pleases. I 
have very little doubt, indeed, that the great reason why this theory 
has been so little opposed, lies in the conviction which I have shared 
with others, that if only it is let alone it will commit suicide. The 
internal evidence is so strong, be the theory true or false, that its 
chief advocates have not had the practical knowledge which they 
ought to have possessed, that I am not in the least surprised that 
those who are best acquainted with fungi and lichens did not deem 
