2 INTRODUCTORY 



compared to a giant amoeba, and justifies in so far the views of those 

 systematists who would remove the slime-moulds from the domain of 

 the botanist altogether, and call them animals. The Plasmodium is 

 often quite large. It may frequently be found covering with mani- 

 fold ramifications and net-like sheets the surface of some convenient 

 substratum for the space of several square feet. 



The substance of the Plasmodium has about the consistency of the 

 white of an egg; is slippery to the touch, tasteless, and odorless. 

 Plasmodia vary in color in different species and at different times in 

 the same species. The prevailing color is yellow, but may be brown, 

 orange, red, ruby-red, violet, in fact any tint, even green. Young 

 Plasmodia in certain species are colorless (as in Diderma floriforme) , 

 while many have a peculiar ecru-white or creamy tint difficult to 

 define. Not only does the color change, sometimes more than once 

 in the course of the life history of the same species, but it may be the 

 same for several forms, which in fruit are singularly diverse indeed, 

 so that the mere color of the Plasmodium brings small assistance to 

 the systematist. In fact, the color depends no doubt upon the pres- 

 ence in the plasmodium of various matters, more or less foreign, un- 

 assimilated, possibly some of them excretory, differing from day to 

 day. 



In its plasmodial state, as has been said, the slime-mould affects 

 damp or moist situations, and during warm weather in such places 

 spreads over all moist surfaces, creeps through the interstices of the 

 rotting bark, spreads between the cells, between the growth-layers of 

 the wood, runs in corded vein-like nets between the wood and bark, 

 and finds in all these cases nutrition in the products of organic de- 

 composition. Such a Plasmodium may be divided, and so long as 

 suitable surroundings are maintained, each part will manifest all the 

 properties of the whole. Parts of the same plasmodium will even 

 coalesce again. If a piece of plasmodium-bearing wood be brought 

 indoors, be protected from desiccation by aid of a moist dark cham- 

 ber, not too warm (70° F.), the organism seems to suffer little if 

 any injury, but will continue for days or weeks to manifest all the 

 phenomena of living matter. Thus, under such circumstances, the 

 Plasmodium will constantly change shape and position, can be in- 



