452 SECOND PART. — Ml'CETOZOA. 



they live on dead organic and especially vegetable substances, of course with the 

 necessary ash-constituents, and are found therefore chiefly in accumulations of 

 dead parts of plants — leaves, tan, rotten wood, and the like. What definite chemical 

 substance does actually and usually serve or is fitted to serve as nutrient material 

 to the Myxomycetes is a question which has not yet been thoroughly examined. 



The facts recorded above show that the food is taken in during the swarm-cell 

 condition only in the fluid state or state of solution, and this is also the case, at least in 

 most instances, with the plasmodia. That it is so appears, to say the least, extremely 

 probable by the behaviour of the plasmodia of Fuligo to the extract of tan, as shown 

 by Stahl's experiments quoted above. This agrees with the observation that 

 plasmodia of Chondrioderma difforme may be obtained from spores in watery 

 infusions of vegetable substances though no solid bodies are supplied to them, and 

 lastly with the fact that solid ingesta have never been found in the plasmodia of 

 certain species, as Lycogala, though it must be allowed that these have not been very 

 thoroughly examined. 



On the other hand we see solid bodies taken up by the plasmodia which have 

 been more particularly described above, among others by Chondrioderma, and some 

 of them at least again thrown out. The body taken into the plasmodium is often more 

 or less perfectly dissolved. It has already been stated that the sclerotium-cells 

 of a species engulphed by its own plasmodium gradually disappear and pass into 

 the substance of the plasmodium, but it is uncertain whether this is a case of actual 

 dissolution of the body introduced, or of a coalescence with the body which absorbs 

 it, like that of the swarm-cells or the branches of the plasmodium. In the plasmodium 

 of Didymium Serpula which were fed with carmine, the fragments of carmine were to 

 some extent at least dissolved ; they were repeatedly carried along in the stream of 

 granules, and in twenty-four hours' time were enclosed each in a vacuole filled with a 

 clear red solution. This continued for several days. On the other hand the 

 Chondrioderma mentioned above showed no signs of dissolving the few fragments of 

 carmine which it received into its substance. In experiments instituted by Dr. 

 Wortmann a number of starch-grains were taken in by plasmodia of Fuligo, and they 

 showed deep corrosions in the course of from two to three days. This shows 

 the presence of a ferment capable of dissolving starch and confirms Kuhne's previous 

 determination. A ferment which acts upon cellulose must be present, at least during 

 the passage of the sclerotia of Fuligo into the motile condition, because the cellulo-e 

 membranes are rapidly dissolved during that time. Krukenberg has ascertained the 

 presence of a peptonising ferment 1 . 



These facts all point to the conclusion that the solid ingesta are to some extent 

 at least appropriated as food and digested, the undigested remainder being then cast 

 out. We have no exact physiological investigations of these questions and of others 

 which are connected with them. So far as plasmodia devour and digest living bodies, 

 the name of saprophytes can only be applied to them with some modification of its 

 ordinary mean. 



Some of the forms which were classed above as doubtful Myxomycetes, Bursulla 

 for example, are saprophytes in their mode of life. The account given above of 



1 Unters. d. physiol. Instit. z. Heidelberg, II, p. 273. Sec also Revoke cited on p. 52. 



