148 PROTISTS AND DISEASE 



placed on fungi other than Stereum varies considerably in its 

 relation : it crept all over a Coprinus, but was destroyed, 

 if it had not crept off when the fungus decayed ; it con- 

 sumed every part of Boletus flavus ; but did not consume 

 any part of Lycoperdon gemmatum. 



The nutrition of species that grow in woody tissue has 

 been inferred to be derived from solutions. De Bary gives 

 the appearance of plasmodia of Lycogala in a section of fir- 

 wood lobulated protoplasmic masses, with no definite 

 relation to the cell- walls of the wood. 



The chemical composition of the plasmodium of Fuligo 

 as described in 1881 is still quoted as being characteristic of 

 protoplasm in general. 



A parasitic mycetozoon. Hymenobolus parasiticus was 

 found in Austria by Zukal in 1893 ; the species has been 

 found also in Scotland. The plasmodium of Hymenobolus 

 has no rhythmic circulation, and instead of spreading in a 

 network it forms a compact mass which eats its way into 

 the lichen or alga on which it feeds. In drought it contracts 

 to form a rose-coloured macrocyst. Its sporangia, which 

 usually have a lid, are drab or, from refuse matter, black. 

 Hymenobolus has no capillitium. 



Culture of a Mycetozoon. Some Mycetozoa in cultures 

 pass rapidly into the sporangial state, but B. utricularis 

 can be kept in the plasmodial state almost indefinitely by 

 supplying it regularly with fresh Stereum. 



Fragments of this fungus placed with water in a vessel 



