THE RELATION OF PLANT PROTOPLASM TO ITS ENVIRONMENT 



By John Muirhead Macfarlane, D.Sc. 





In discussions regarding the origin and the relations of plant and animal 

 cells to their environment, we too often select and speak of the more highly 

 organized groups of plants and animals, or of these when in the actively vege- 

 tating and reproductive phases. And so we treat of cells that consist of the 

 more generalized substance protoplasm alongside the more specialized substance 

 nuclear chromatin, while we ordinarily study both in their most active state. 



But alike for the primitive origin of plants and animals, their means of 

 dissemination and perpetuation, as well as their relation to higher forms, it is of 

 prime importance that we should try to get exact conceptions as to the most 

 primitive and most simple organisms, as well as the endurance capacity of the 

 highest types now living. 



The aim of this paper is to record observations, and to bring together results, 

 that may aid us in our estimation of the life capacities of plant protoplasm. 

 The writer has also brought together results, which he hopes to publish in time, 

 bearing on animal protoplasm, and which show that between both there is a 

 fundamental agreement. 



While we would by no means consider that protoplasm is so simple a substance 

 that it can, or probably will, be generated by the physiological chemist, on a few 

 minutes' or a few hours' notice, we would equally consider that all experimental 

 evidence indicates that it primitively originated by slow natural processes, at a 

 stage in the world's history, when physico-chemical surroundings had become 

 such as to favor actions and reactions that gradually resulted in its formation. 



It becomes then a matter of high value to ascertain whether evidence can now 

 be secured, that would aid us toward a solution of its mode of origin. In such 

 an inquiry also, it will readily be conceded that the four great environmental 

 factors which determine synthetic and analytic activities are temperature, 

 light, electro-chemical action and water supply. Further if living organisms 

 are to aid us in our interpretation of past existence, our studies should begin 

 with those simplest forms that consist of non-nucleate protoplasm. In attempt- 

 ing to follow out such a line of inquiry, some biologists have emphasized the 

 importance of types like the Myxomycetes and the Lobosa, as being irregular 

 protoplasmic aggregations which ingest food, often in a solid state. But apart 

 from the beautiful nuclei and nucleoli that these show, as well as the karyokinetic 

 phases exhibited in their cell division, we would regard their mode of food ab- 

 sorption as a specialized— not a primitive— one. Even did we know more 

 accurately regarding such forms as Chlamydomyxa amongst plants, and Proto- 



251 



\ 



