14 DIVISION 1.—GENERAL MORPHOLOGY. 
this alteration consists in the removal of some substance which was present from the 
first must remain uncertain; such an explanation has not been proved and others 
are at least possible. Without going further into the question here, we may merely 
recall the fact, that ordinary cellulose is coloured blue by iodine when certain reagents 
have produced certain changes in it; but zinc chloride, for instance, does not in this 
process remove some admixture which is present in the cellulose and prevents it from 
turning blue. Old threads of linen and cotton which have been repeatedly washed 
become blue at once in a dilute solution of iodine; the changes in their original 
condition which are thus indicated cannot consist in the simple removal of any 
substance. From such considerations it appears to me that the cause of the peculiar 
character of the Fungus-cellulose is not yet ascertained, and the harmless special 
name for it seems still to be desirable. 
Coloration. The colouring-matters which are peculiar to the Fungi, i.e. which 
are produced in their metabolism, are chiefly if not solely the yellow and the reddish 
yellow which are partly attached to the fatty or fat-like contents of the cells, and 
partly disseminated through the membranes. It is not therefore too much to say, 
that all tints peculiar to the Fungi, which do not belong to the first category, proceed 
from the specific colour of the membranes. 
An exception to this rule, which may perhaps be regarded as only apparent, is 
said to occur in some normally colourless moulds and parasitic forms, which growing 
in water on a substratum containing soluble red and violet colouring matters take 
up these unaltered in such a manner that even their cell-contents are corre- 
spondingly coloured. Fresenius? makes a similar statement with respect ‘to species 
of moulds growing among red-coloured Micrococcus prodigiosus, Cohn; I found 
the same thing in Eurotium and in species of Mucor growing on red fruits and in 
Phytophthora infestans on red and blue potatoes. But I am now doubtful, firstly 
whether the colouring of the cell contents is in the protoplasm or in the cell-sap or 
in both, and secondly whether it is present in the living Fungus, or appears only 
in those of its cells which have been killed in making the preparation and have then 
taken up the colouring matter into their protoplasm. 
One thing remains to be noticed here which has never yet been explained, the 
colouring of Peziza aeruginosa, P. (Chlorosplenium aeruginosum of Tulasne) *. 
This Fungus is found on wood with the green rot so common in forests, the colouring 
matter of which has been frequently examined since Vauquelin’s time and most re- 
cently by Prillieux. The green colouring matter of this wood is usually contained 
in its cell-walls, but sometimes forms according to Prillieux in amorphous masses 
in the cavities of the wood elements. This is in many cases all that is to be seen; 
over wide spaces on and in the wood there is no trace of a coloured or uncoloured 
Fungus to be seen; (Gümbel, Fordos, and myself). Ifa Peziza occurs on and in wood 
of this kind, almost all parts of it are coloured green, and the colour is in the mem- 
branes and perhaps also in the interior of the cells of the Fungus, and often in 
such quantity that the Fungus is more deeply coloured than the wood itself. Single 
fructifications of the Peziza however rising from the wood are sometimes uncoloured, 
a pure white, in their upper parts which are farthest from the surface of the wood. 
These facts taken together led to the view that the green colouring matter is a 
product of the decomposition of the wood without the co-operation of the Peziza, 
which takes it up unaltered when it settles in the wood. The fact that Peziza 
aeruginosa only grows, as far as is known, on this green-rotting wood, and on no 
other substance, is not in itself a valid objection to this view. But there are on the 
other hand so many established instances of specific decompositions effected by 
certain Fungi, that the repeated confirmation of the above-mentioned fact and the 
absence of other species of Fungus were constantly suggesting the idea that the 

! Beitr. 80. 2 Carpol. III, p. 188. 
