AS RESERVE-MATERIAL IN PLANTS. 



29 



weeks of cultivation. The albumen of our proteosomes therefore 

 serves for building up protoplasm. — If we place now the same 

 threads in a solution containing potassium-nitrate, as for in- 

 stance in : 



0,05 per cent potassium nitrate, 



0,03 ,, ,, calcium nitrate, 



0,005 " " magnesium sulphate, 



0,005 " " monopotassium phosphate, 



trace chloride of iron, 

 we obtain after 3 weeks with coffein an intense formation of 

 proteosomes, more active albumen having been produced than 

 was required for organisatory purposes. Potassium nitrate is 

 not only a suitable source of nitrogen, but the potassium of this 

 salt is also important for the chlorophyll function, yielding an 

 increased quantity of starch for the synthesis of proteids. Spiro- 

 gyra majuscula forms in this solution after several weeks such 

 large quantities of active albumen, that this commences in some 

 cells to separate in globules even without the coffein-treatment.— 



Also changes of temperature have a great influence. Hot 

 weather favors growth and the active albumen may be more 

 quickly used than formed ; hence a decrease of the reserve- 

 albumen ; if now cold weather follows, growth is more retarded 

 than the synthetical preparation of proteids, hence an accumula- 

 tion of active albumen results. r) — Also phosphates interfere 

 with the accumulation. In the absence of these salts (other 

 conditions being favorable) albumen will continue to be formed, 

 but organisation and multiplication of cells will have stopped, 

 hence accumulation increases.^ 



1) It was quite natural for us to take, at the beginning of our studies, the 

 proteosomes of the cytoplasm for an essential part of the protoplasm, as it was not 

 known before, that dissolved proteids occur as reserve material in the living pro- 

 toplasm itself. The recent attack of P. KUmm upon our definition of active albumen 

 (Hot. C. March 1894) contains no arguments, but merely a series of assumptions 

 disregarding the main facts we described, especially the most important change 

 of the proteosomes as soon as the cells are killed in one way or other. 



The state of copulation does not depend upon the amount of stored up active 

 albumen ; I have observed in some cases much of the latter, in other cases none 

 at all.— 



2) O. Loew, On the physiological functions of phosphoric acid ; Biolog. Cent- 

 ralbl. Vol 11. p. 280. 



