264 RELATION OF PLANT PROTOPLASM TO ENVIRONMENT. 



One is tempted now to inquire as to the action of environmental light rays on 

 both of the schizophytic groups. Unfortunately our knowledge is still so limited, 

 that we can only speak with reasonable certainty along one line. Several sets 

 of experiments, from those of Ward onward, demonstrate that when light passes 

 a definite maximum of intensity it becomes injurious and even actively de- 

 structive. Thus in Microbiology (18) we read "most bacteria are killed by direct 

 sunlight in a few hours/' and "the different colors of the spectrum do not act 

 alike; the part of the spectrum from red to green is practically without influence 

 upon microorganisms, while the blue light acts strongest, and the intensity de- 

 creases in the violet and ultra-violet. ' ' This is exactly true of the higher nucleate 

 plants, as first pointed out by the writer (19). 



In proceeding now from the Protophyta or non-nucleate to the Metaphyta 

 or nucleate plants, a noteworthy feature is that the cell or several cells that 

 make up each mature organism, tend to become greatly vacuolated by absorption 

 of relatively large supplies of water, while the chromatin that was absent, or pres- 

 ent in a more or less " amphiplasmic ' ' state becomes definitely aggregated into 

 nuclear and nucleolar constituents. Possibly one, perhaps both of these changes 

 may limit adaptability to diverse environmental conditions, and not least di- 

 verse temperatures, though the writer would lay greatest stress on water content. 

 But when most metaphytic cells — the egg and sperm mainly excepted — become 

 richly protoplasmic, or are protected by mucilaginous or pigmented cellulose or 

 lignin coats, or pass by definite cyclic relation into a dormant resting state where 

 the stored food and the granular protoplasm are relatively great in amount, and 

 the nuclear chromatin is relatively small and surrounded by the former, a like 

 wide range of protoplasmic adaptability to environment is witnessed. 



Though greatly more extended and minute experiment and observation are 

 needed, enough results have been secured to guide us. These we will treat of, 

 in gradually ascending series, beginning with the algae and fungi. 



Alike because growing algoid cells are usually much vacuolated, and the 

 resting spores have been little experimented with, our information as to algse 

 is still scant. 



According to the temperature records given by West (20) for the material 

 collected by A. W. Hill at hot springs in Iceland, not only blue-green algse but 

 numerous species of diatom, three species of the Desmid Cosmarium and even a 

 species of Zygnema live at temperatures of 49° to 61° C, thus apparently con- 

 firming Berggren's and Borgesen's accounts for New Zealand and Iceland. 

 A more careful study of such higher algae in relation to environment is greatly 

 to be desired however. But amongst fungi we know that yeasts such as S. 

 cerevisioe and S. hansenii can live after several days' exposure to — 70°-100° C, 

 though vegetative activity starts about 10° C. From the latter temperature 

 upward, yeast continues to bud in nutritive solution, according to A. Meyer, 

 up to 53° C, while air dried yeast remains alive up to 100° or 110° C. The 

 duration of life, at optimum temperature, of pressed yeast is stated by Claude 

 Bernard and Schumacher to continue for two years. 



