CHAPTER I,—HISTOLOGICAL CHARACTERISTICS, 7. 
colouring matter or amylum-grains, nor, asfar as is known, any vehicles for colouring 
matters nor their homologous pdastéds (A. Meyer’s trophoplasts). 
It would appear that the formation of fatty matters takes the place very generally 
of the amylogenesis which holds in plants containing chlorophyll; these matters 
always form a percentage of the dry substance of vegetating Fungi, and may 
amount with diminution of the proteid substances to 50 per cent. of the material 
stored up in the resting-states, to 35 per cent. in the fatty sclerotia of plants like 
Claviceps, and to 50 per cent. in the Moulds (? Penicillium) in the resting or 
involution-stage, that is, after the close of vegetation. During the time of active 
vegetation the fatty substances are disseminated in the form of minute drops in 
the protoplasm of the cells of Fungi, as they are in the cells of other plants, and 
help to make it look granular or turbid; in the resting states (periods of involution), 
in which reserve-material is stored up, they may collect into large strongly refringent 
drops which occupy the largest part of the cell-cavity. Examples of the latter case 
are the sclerotia of Claviceps, the thallus of Sphaeria Stigma, Fr., S. discreta, Schw., 
S. eutypa, Fr., Vermicularia minor, old moulds, many spores, &c. &c. 
In many cases the collections of fatty matter are colourless or only faintly 
coloured, but sometimes they are very highly coloured, if after the analogy of cases 
which have been carefully and chemically examined we may venture to apply the 
term fatty substance to bodies, of which we only know with certainty that they agree 
with fatty aggregates in outward appearance and in the ordinary microchemical 
reactions. If the bodies in question are really to be regarded as chemically 
definite fats, it still remains to be decided whether the colours belong to the fats 
themselves, or are derived from distinct colouring matters which would in that case 
be attached to the aggregates of fatty matters as their vehicles. With this reservation 
and pending the requisite strict chemical examination, we may designate as coloured 
aggregates of fatty substances those microchemically fat-like bodies which produce 
the characteristic colouring from yellow to brick-red in so many Fungi—Uredineae, 
Tremellineae, Stereum hirsutum, Sphaerobolus, Pilobolus, many Pezizas as P. aurantia, 
P. fulgens’, and various other kinds. They are found thinly disseminated ‚in the 
protoplasm of actively vegetating and growing cells, imparting to it a uniform 
colouring ; after the death of the cells they often run together into larger drops ; 
in older cells also they sometimes assume this form spontaneously. In the Uredineae, 
and according to Coemans in species of Pilobolus also, the red colouring matter 
shows a characteristic reaction, becoming intensely blue when treated with sulphuric 
acid, then quickly passing into a dirty green and then gradually losing all colour, 
a reaction which is seen in the similar red colouring matter of many parts of plants 
which do not belong to the Fungi, and in the red pigment-spots (eye-spots) of 
some of the lower forms of animal life. This reaction is not found in the other 
Fungi mentioned above. These facts sufficiently point to a different material 
composition of the bodies in question in different cases: some of them were 
spectroscopically examined by Sorby. 
Van Tieghem discovered crysfalloids of albuminoid substance (mucorim) in 
the gonidiophores and zygosporophores of most of the Mucorini. J. Klein found 

1 P. fulgens, Fr., was named P. cyanoderma in the first edition of this book. 
