395 
of Edinburgh, Session 1881 - 82 . 
only do the algal constituents of lichens thrive better and live 
longer in association with fungi than similar algse living free, but 
that the same takes place in other cases, thus in the leaves of 
numerous phanerogams, where those parenchyma cells, which are 
directly attacked by the hypha of the parasite, live much longer 
than the rest. He explains this “par le retour des matieres 
nutritives vers les centres de reserve que le mycelium contre- 
balance,” an expression which I do not very clearly understand. 
He further explains that in the algae of lichens reproduction 
and development of spores is impeded, and vegetative life thus 
prolonged and enhanced, just as by preventing flowering the life 
of annuals may be prolonged. This is all doubtless true, but it 
seems to me likely that a very important factor in the healthy 
nutrition of the alga would be afforded by the endosmose of the 
waste products of the fungal protoplasm in return for the exosmose 
of its starch, &c. Doubtless this is included in Van Tieghem’s 
view of “mutual parasitism,” to what M. Cornu alludes, but to 
which I have not been able to refer. 
G. So far as I am aware, the only remaining recent contribution 
to the literature of this subject is the paper by Professor Ray 
Lankester,* above referred to, in which he gives a full description, 
with figures, of the chlorophyll corpuscles and amyloid deposits of 
Hydra and Sjpongilla , together with a criticism of the views of 
Dr. Brandt to which I have already concurred. Mr. Lankester, 
however, lays what appears to me undue stress on the importance 
of the spectroscopic identification and analysis of chlorophyll, a 
mode of research which, as shown above, and as he indeed freely 
admits, has led to faulty results, and he has overlooked that I 
have clearly stated that the green colouring matter of Convoluta + is 
true chlorophyll, having the usual solubility and fluorescence, and 
giving a spectrum closely resembling that of vegetable chlorophyll. 
I have also described the structural form in which the pigment 
occurs, J as uniformly diffused through the "semi-fluid protoplasm of 
nucleated and granular cells, lying below the muscular layers of the 
integument, not collected into granules as in plants, nor in drops as 
* Quart. Jour. Micro. Sci . , April 1882. 
t “ Observations on the Physiology and Histology of Convoluta Schultzii,” 
Proc. Roy. Soc. Lond., No. 194, 1879, p. 452. 
+ Ibid., p. 454. 
VOL. XI. 3 E 
