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 SplachnacecB, 

 and that it has selected the cow-dung to be its nutrient substratum. Each growth 

 of emerald green, Splachnum ampullaceum, 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 protonemae, 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 ampullaceum 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 Splachnacece, are true saprophytes- A similar remark 

 holds with regard to the green Euglence 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 organic 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 



