14 REPORT 1879. 



resisting the entrance of colouring matter into its substance. As many 

 here present are aware, microscopists are in the habit of using in their 

 investigations various colouring matters, such as solutions of carmine^ 

 These act differently on the different tissues, staining some, for example, 

 more deeply than others, and thus enabling the histologist to detect 

 certain elements of structure, which would otherwise remain unknown. 

 Now if a solution of carmine be brought into contact with living proto- 

 plasm, this will remain, so long as it continues alive, unaffected by the 

 colouring matter. But if the protoplasm be killed the carmine will at 

 once pervade its whole substance, and stain it throughout with a colour 

 more intense than even that of the colouring solution itself. 



But no more illustrative example can be offered of the properties of 

 protoplasm as living matter, independently of any part it may take in 

 organisation, than that presented by the Myxomycetae. 



The Myxomycetaa constitute a group of remarkable organisms, which, 

 from their comparatively large size and their consisting, during a great 

 part of their lives, of naked protoplasm, have afforded a fine field for 

 research, and have become one of the chief sources from which our know- 

 ledge of the nature and phenomena of protoplasm has been derived. 



They have generally been associated by botanists with the Fungi, but 

 though their affinities with these are perhaps closer than with any other 

 plants, they differ from them in so many points, especially in their deve- 

 lopment, as to render this association untenable. They are found in 

 moist situations, growing on old tan or on moss, or decaying leaves or 

 rotten wood, over which they spread in the form of a network of naked 

 protoplasmic filaments, of a soft creamy consistence, and usually of a 

 yellowish colour. 



Under the microscope, the filaments of the network exhibit active 

 spontaneous movements, which, in the larger branches, are visible under 

 an ordinary lens, or even by the naked eye. A succession of undulations 

 may then be noticed passing along the course of the threads. Under 

 higher magnifying powers, a constant movement of granules may be seen 

 flowing along the threads, and streaming from branch to branch of this 

 wonderful network. Here and there offshoots of the protoplasm are 

 projected, and again withdrawn in the manner of the pseudopodia of an 

 Amoeba, while the whole organism may be occasionally seen to abandon 

 the support over which it had grown, and to creep over neighbouring 

 surfaces, thus far resembling in all respects a colossal ramified Amoeba. 

 It is also curiously sensitive to light, and may be sometimes found to have 

 retreated during the day to the dark side of the leaves, or into the recesses 

 of the tan over which it had been growing, and again to creep out on the 

 approach of night. 



After a time there arise from the surface of this protoplasmic net oval 

 capsules or spore-cases, in which are contained the spores or reproduc- 

 tive bodies of the Myxomycetse. When the spore-case has arrived at ma- 

 turity, it bursts and allows the spores to escape. These are in the form. 



