654 SUMMARY OF CURRENT RESEARCHES RELATING TO 



peculiar property of storing up an oxcess or rcsorvo of nitrates 

 especially in the medullary parenchyma of the stem and in tho 

 cortical parenchyma. This reserve is greatest at tho period 

 immediately prccoding tho flowering ; tho nitrates are then stored 

 chiefly in the lower third of the stem, and are designed for tho nutri- 

 ment of tho physiological summit of the plant, namely tho flowering 

 axis. If a branch containing nitrates in the stem, and showing a 

 flowering axis, be cut off and plunged in distilled water, the nitrates 

 soon disappear, and as they are not found in the water, must bo con- 

 sidered to have been used by the plant. Also, if a branch of this 

 sort bo cut off above the reserve of nitrates and plunged in a 

 0*004 solution of potassium nitrate, sections just below the flowers 

 soon show tho presence of nitrates. Tho power of accumulating 

 nitrates is a specific property of certain plants. Among those 

 particularly rich in this reserve of nitrates are Solatium tuberosum, 

 Urtica dioica, Mercurialis annua, Sittapis alba, Brassica oleracea, 

 Spinacia oleracea. Amongst those not containing nitrates in excess 

 are Senecio vulgaris, Syringa vulgaris, Viola tricolor, Malva, Bumex, 

 Pliaseolus, and Chrysanthemum. Berthelot and Andre consider that 

 the cells of the stem bave the power of elaborating nitrates. 

 Boussingault's opinion, which is corroborated by the author's experi- 

 ments, was that the nitrates enter the plant as such from without, and 

 arc assimilated in the plant. Branches of dahlia, selected when free 

 from nitrates, and plunged into a solution of ammonium sulphate, 

 have never shown the formation of nitrates in their tissues. The 

 author suggests that exhausting crops are those which possess the 

 special property of storing up nitrates. 



Action of Salicylic Acid on Ferments.* — Mr. A. B. Griffiths 

 finds that a solution containing • 2 gr. of salicylic acid per 1000 c.cm. 

 of water destroys very quickly Mycoderma aceti, Bacterium lactis, and 

 the butyric bacillus. It appears to act on and dissolve the cell-walls 

 of these organisms, as also of dead Torulse ; although living Torulse 

 are not acted on, nevertheless their activity is impeded by the 

 salicylic acid. Thus neither yeast nor saliva exert their fermenta- 

 tive faculties in the presence of this solution of salicylic acid. The 

 yeast can, however, be revivified by treatment with sodium phosphate 

 and potassium nitrate. Hence " diseased yeast " may be advan- 

 tageously treated with such a solution of salicylic acid which is far 

 below the poisonous strength. 



Behaviour of Guanin, Xanthin, and Hypoxanthin in the 

 Fermentation of Yeast. j — Meaning by hypoxanthin, hypoxanthin 

 4- adenin, Herr V. Lehmann finds that when yeast is allowed to 

 stand in water at the ordinary temperature of a room, only small 

 traces of these bases are set free from the nuclein; while if the 

 temperature is that of the body, the entire quantity of hypoxanthin 

 is smaller, that of guanin -f- xanthin larger. 



* Chem. News, liii. (1886) pp. 28-9. 



t Zeitschr. f. Physiol. Ohemie, ix. (1885) pp. 563-5. See Bot. Central bl., 

 xxvi. (1886) p. 101. 



