THE PROTOPLAST 



21 



thyme (fig. 39) and the grass-like leaves of that river wonder, VaUisneria 

 spiralis; for here there are no stationary nuclei, but the whole of the 

 protoplasm moves round and round. In some instances this movement is 

 found to take place in opposite directions in contiguous cells, observation 

 of this interesting fact being facilitated by the presence in the trans- 

 parent protoplasm of minute grains of a green colouring matter (chloro- 

 phyll), which are carried round with the stream, and thus discover its 

 course. The layers of living matter in which these corpuscles float are 

 frequently no more than ^^^th of an inch in depth ! What, then, must be 

 the dimensions of the green grains themselves ? 



Probably enough has now been said, at least for the present, about the 

 remarkable properties of protoplasm. We have seen that the little specks 

 of germinal matter the protoplasts, if you please are the weavers of the 

 warp and woof of organisms the builders, may we not say? of all animal 

 and vegetable structures whatsoever. They constitute, indeed, " the 

 physical basis of life," and are the fabricators of every object that lives 

 or has lived ! 



Is it not wonderful to think of our little protoplasts even as the builders 

 of a single plant ? Conceive of them, for example, as the fabricators of a 

 Sweet Briar-rose. Here a number of them are busy at work in their 

 self-formed cells, and they 

 throw out material as what '? 

 As incipient hairs. Here are 

 numbers more equally as busy, 

 and they are producing material 

 which will be built up into 

 woody fibre. Others, close at 

 hand, are constructing a wonder- 

 ful layer of similar cells, each 

 with its own protoplasm, its 

 own walls, its own cell-sap. 

 Thus in one part of the plant 

 we have our root-hairs ; in 

 another, our woody fibre ; and 

 in a third, some delicate tissue 

 of cells which is to aid in the 

 formation of a petal, a foliage 

 leaf, or perchance a seed. All 

 this, remember, in a single 

 plant ! Yet the little workers 

 are chemically alike in each 

 case; and all consist of the 

 same elementary substances. 



/ Photo by] [\V. Plomer Young. 



And as With our sample FIG. 38. SENSITIVE PLANT (Mimosa pudica). 



