SAPROPHYTES AND THEIR RELATION TO DECAYING BODIES. 103 
processes in detail later on, but the fact must be taken into consideration here. 
One would suppose, accordingly, that plants able to obtain ready-made organic 
compounds from a nutrient substratum could spare themselves the trouble of 
building them up, so that the presence of chlorophyll would be superfluous. 
This conjecture is in fact supported by the absence of chlorophyll in fungi, which 
are typical instances of saprophytes. But, on the other hand, some plants appear 
to negative this assumption, or at any rate to deprive it of general application. 
In mountain districts, where cattle continually pass to and from the meadows and 
alps, one notices on their halting grounds, and along their tracks, moss of a con- 
spicuous green colour growing on circumscribed spots. On closer examination we 
find that we have here an example of the remarkable group of the Splachnacee, 
and that it has selected the cow-dung to be its nutrient substratum. Each growth 
of emerald green, Splachnum ampullacewm, is strictly limited to the area of a 
lump of dung; no trace of it is to be seen elsewhere. All the stages of development 
of this moss follow one another upon the same substratum. First of all the lumps 
of dirt which are kept moist by rain or by standing water, become enveloped in 
a web of protoneme, and their surfaces acquire thereby a characteristic greenish 
lustre. Later, hundreds of little green stems, thickly clothed with leaves, emerge, 
and the spore-cases, which resemble tiny antique jars, and are amongst the 
prettiest exhibited by the world of mosses, become visible as well. Just as 
Splachnum ampullacewm is produced on the dung of cattle, so is Tetraplodon 
angustatus on that of carnivorous animals, and there can be no doubt that 
these, and in general all Splachnacew, are true saprophytes. A similar remark 
holds with regard to the green Huglene which escape from Hormidium-cells, and 
fill the foul-smelling liquor in dung-pits and puddles near cattle-stalls in mountain 
villages, and which multiply to such an extent that in a few days the liquid 
changes colour from brown to green. 
Thus plants do exist containing chlorophyll although absorbing from the 
substratum organic compounds alone, and containing it, indeed, in such quantities 
that its presence cannot be looked upon as accidental. It follows, firstly, that 
absence of chlorophyll is not the distinguishing mark of saprophytic plants; and, 
secondly, that the organie nutriment of the plants above mentioned cannot be used 
forthwith unaltered in the building up and extension of their structures, but, like 
inorganic material, must undergo various changes, that is, must be to a certain 
extent digested before being used for construction. The probability is that green 
saprophytes take carbon from their substratum in a form unfitted for the manu- 
facture of cellulose and other carbohydrates. Saprophytes that are not green 
must obtain carbon from the substratum in the form of a compound, the direct 
absorption of which could be dispensed with if chlorophyll were present; but it 
does not necessarily follow that all the organic compounds absorbed by non-green 
saprophytes are capable of immediate service as materials for construction without 
any preliminary alteration. 
Impartial consideration of the above facts forces us to conclude that there is no 
