CHEMICAL AND PHYSICAL PROPERTIES. 



197 



and be all ready for examination, with no disturbance whatever. 

 If the Plasmodium is allowed to creep over the face of a slide 

 placed horizontally, it is apt to be too thick for a demonstration 

 of some of the points which are now to be referred to. 



541. Chemical and physical properties of protoplasm. When 

 the Plasmodia of ^thalium septicum collect in large masses on 

 ths surface of spent tan, they afford good material for the exam- 

 ination of some of the chemical and phj'sical characters of pro- 

 toplasm ; but there is, of course, the serious objection that it 

 is impossible to obtain the protoplasm in a state of absolute 

 purity. Upon such material, however, Reiuke and Eodewald-^ 

 have conducted some instructive experiments, the principal re- 

 sults of which are detailed in the following paragraphs. 



542. The organic substance of the protoplasm of jEthalium 

 proved to have the following elementary composition : ^ — 



1 Studien iiber das Protoplasma, Berlin, 1881. 



^ The compo.sitiou of the air-dried substance is approximately as follows ; 



Water 4.80 



Pepsin and Myosin 1 .00 



Vitellin 5.00 



Plastin 27.40 



Guanin J 



Xanthin > 01 



Sarkin ) 



Ammonic carbonate 10 



Asparagin and other amides 1.00 



Pepton and Peptonoid ■ 4.00 



Lecithin 20 



Glycogen 4.73 



iEthalium sugar 3.00 



Calcic compounds of higher fatty acids ... 5.33 

 Calcic formate ) .2 



Calcic acetate i ' ' ' 



Calcic carbonate 27.70 



Sodic chloride 10 



Hydropotassic phosphate (PO4K2H) .... 1.21 

 Iron phosphate (POjFe ?) 07 



