176 DROSERA ROTUNDIPOLIA. [Chap. IX. 



absorbed from these five weak solutions, and yet, owing to the 

 presence of the salts, did not prevent the subsequent action of the 

 phosphate? Or may we not suppose' that the interstices of the 

 walls of the glands were blocked up with the molecules of these 

 five substances, so that they were rendered impermeable to water; 

 for had water entered, we know from the ten trials that the phos- 

 phate would not afterwards have produced any eflcct? It further 

 appears that the molecules of the carbonate of ammonia can quick- 

 ly pass into glands which,' from having been immersed for 20 m. in 

 a weak solution of sugar, either absorb the phosphate very slowly 

 or are acted on by it very slowly. On the other hand, glands, how- 

 ever they may have been treated, seem easily to permit the subse- 

 quent entrance of the molecules of carbonate of ammonia. Thus 

 leaves which had been immersed in a solution (of one part to 437 of 

 water) of nitrate of potassium for 48 hrs. of sulphate of potas- 

 sium for 24 hrs. and of the chloride of potassium for 25 hrs. on 

 being placeil in a solution of one part of carbonate of ammonia to 

 218 of water, had their glands imme<liately blackened, and after 

 1 hr. their tentacles somewhat inflected, and the protoplasm aggre- 

 gated. But it would be an endless task to endeavour to ascertain 

 the wonderfully diversified effects of various solutions on Drosera. 



Alcohol (one part to seven of water). It has already been 

 shown that half-minims of tliis strength placed on the discs of 

 leaves do not cause any inflection; and that when two days after- 

 wards the leaves were given bits of meat, they became strongly in- 

 flected. Four leaves were immersed in this mixture, and two of 

 them after 30 m. were brushed with a camel-hair brush, like leaves 

 in a solution of camphor, but this produced no eflTect. Nor did 

 these four leaves, on being left for 24 hrs. in the diluted alcohol, 

 undergo any inflection. They were then removed ; one being placed 

 in an infusion of raw meat, and bits of meat on the discs of the 

 other three, with their stalks in water. Next_,day one seemed a 

 little injured, whilst two others showed merely a trace of inflection. 

 We must, however, bear in mind that immersion for 24 hrs. in 

 water prevents leaves from clasping meat. Hence alcohol of the 

 above strength is not poisonous, nor does it stimulate the leaves 

 like camphor does. 



The vapour of alcohol acts differently. A plant having three 



fire Dr. M. Tmubo's curious By allowing; a precipitation of 



experlinoiits on the production sulphate of barium to take place 



of artllU'lal cells, and on their at the same tlnu>, the mi'mbranc 



porin':iblIlty to various salts, de- boronies " Infiltrated " with this 



8Tlb'd In his papers: " Rxjierl- salt; and In con8i'iuonce of the 



nicnte zur Theorle der Zfllonbll- Intercalation of niotccules of sul- 



dtini; und Kndosmose," Hreslau, phato of l)arliim ariouK those of 



IKIVI; and"Kxpprlm<nte zur physl- the K^latlne precipitate, the niolec- 



callsrhen KrklilnmK dor KlldunR ular Interstices In the membrane 



tier Zfllhaiit, Ihres Wachnthums are made smaller. In this altered 



durch IntusHUsreptlon." Itrcsluu, condition, the membrane no 



1H74. These researches perhaps lonijer allows the passace through 



explain my results. Dr. Tranne It of either sulphate of ammonia 



commonly employed as a mem- or nitrate of barium, thouKh It 



bmne the precipitate formed retains Its permeabliltv for water 



whaa tannic aeld eomes Into con- and chloride of auimonla. 

 taeC wHU BolaUon of gelatine. 



