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 coffeïn 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 coffeïn-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 2) 
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. Klemm upon our definition of active albumen 
(Bot. 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. 
