igoo-i.] Effects of Water on Foliage Leaves. 317 



" Nach einer friiheren Untersuchung ' gehen Keimpflanzen 



der Feuerbohne in distillertem Wasser sehr bald zu Grunde, wahrend 

 dieselben bei Zusatz von KalksaLzen sich vollkommen normal 

 entwickeln. Es sollte nun gepriift werden, ob die Aufnahme des zur 

 Entwickelung nothwendigen Kalksalzes auch durch die Blatter der 

 Feuerbohne geschehen kann. In distillirtem Wasser gezogene 

 Keimpflanzen wurden zu diesem Zwecke taglich drei mal wahrend je 

 15 minuten mit ihrem obern Ende in distillirtem Wasser mit 2 

 pro mille Kalksalz eingetaucht. Diese Pflanzen erhielten sich so 

 lang frisch, bis die cotyledonen eingeschrumpft und bei dem Versuchen 

 im Dunkeln sammtliche Starke aus dem Stengel verschwunden war, 

 wahrend Controlpflanzen, die nicht in die Kalklosung getaucht wurden, 

 friihzeitig abstarben.' " 



This supports the conclusions made by the writer, both in regard to 

 the absorption of water by developing buds and living undetached 

 leaves. 



In regard to the question of the absorption of dilute solutions of 

 poisonous substances there is something to be said. It has generally 

 been held that the copper of the bordeaux mixture is not absorbed by 

 the leaves of plants, but by two special experiments, the writer has been 

 able to prove that CUSO4, m/640, or when applied in a more dilute form, 

 is absorbed. Of course CuSOi is not the compound of copper in the 

 bordeaux mixture, although it is in this form before mixing, still the 

 experiment with CuSOj will apply to the Cu(OH).,, or whatever soluble 

 copper compound may result from the combination of the substances in 

 the mixture. 



If a drop of a dilute solution (m/640) of CUSO4 be placed on the 

 under side of a leaf of Primula stellata, and left for twenty-four hours, 

 no trace of the CUSO4 is found upon the surface, but there is a 

 discolouring, to some extent, of the natural tissue of the leaf. Similar 

 experiments with other salts were performed by Boussingault and b)- 

 Schlossing, and they concluded that if no salt was visible upon the leaf 

 surface, total absorption took place. 



If one were to spot rather freely a similar leaf with a solution of 

 CUSO4, m/640, for four or five successive days, then wash quickly the 

 surface with distilled water, dry, incinerate carefully, collect the ash and 

 dissolve as in qualitative mineral anah'sis; and if, after getting rid of the 

 surplus acid and evaporating down to a small quantity, this solution be 

 placed in a small test-tube, and in the solution a clean, bright iron wire, 



