g. LECTURE VI. 



which they are enabled to creep upwards, they present the striking phenomenon 

 that sooner or later, when the active external movement ceases, they assume 

 definite forms (often in the highest degree characteristic, and resembling those 

 of mushrooms, etc.) and then become 'rigid; solid substances are secreted on 

 the surface, and partly also in the interior, while the remainder breaks up into 

 innumerable round cells. The plasmodium of the Myxomyceies may be con- 

 sidered as the simplest type of a growing plant; a plant which during its growth 

 produces no cell-walls at all, even at its outer surface, but is at the same 

 time able to assume certain simple and characteristic forms. From these relations 

 of form of the plasmodia up to the processes of growth of the Cceloblastse, or 

 non-cellular Algffi and Fungi, there is practically only one step; for if we 

 imagine a plasmodium externally surrounded by a cell-membrane, the latter not 



essentially hindering the configuration 

 of the protoplasm, we have somewhat 

 the same process as in the growth of a 

 Plasmodium ; only with the difference, that 

 by means of the solid outer membrane, 

 less dependence upon the external world 

 and a greater individuality of the con- 

 figuration are attained. If we imagine 

 further that within a Coeloblast, such 

 as a Caulerpa, Vaucheria, Bryopsis, etc., 

 with progressive growth, a cleaving of 

 the protoplasmic mass takes place in the 

 interior by partition walls placed trans- 

 versely and longitudinally, we obtain an 

 ordinary plant, consisting of cell-cham- 

 bers. The continuation of our descrip- 

 tion will show that the ordinary structure 

 of the plant can in fact be understood 

 according to this scheme. Fundamentally, 

 every plant, however highly organised, is 

 a protoplasmic body coherent in itself, 

 which, clothed without by a cell-wall and 

 traversed internally by innumerable transverse and longitudinal walls, grows ; and it 

 appears that the more vigorously this formation of chambers and walls proceeds with 

 the nutrition of the protoplasm, the higher also is the development attained by the 

 total organisation. It is perhaps impossible to make the significance of the pro- 

 toplasm for the life of the plant clear in any other manner than this ; although to 

 those not yet familiar with the facts it certainly cannot be easy to apprehend the 

 true meaning of the matters here stated. Nevertheless it was an ingenious thought 

 of Hofmeister's to put down the apparent creeping motion of the plasmodia of the 

 Myxomycetes, and their later transformation into fructification, as the simplest type of 

 growth, even for more highly organised plants. 



In spite of its internal mobiUty and apparently viscid or slimy consistence, 

 the protoplasm exhibits occasionally, besides the coarser structure already described, 



FIG. Zi,—Dtdymiitm fcirinactttm, a Myxoinycete. The 

 whole structure at first consists of protoplasm, from which the 

 solid fabric here figured is separated out later, while the 

 remainder (inside the capsule) breaks up into spores (after 

 Rostafinski). The stellate bodies on the capsule are crystals. 



