216 DEOSEEA EOTUNDIFOLIA. Chap. IX. 



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 

 phosphate would not afterwards have produced any effect ? It 

 further appears that the molecules of the carbonate of ammonia 

 can quickly pass into glands which, from having been immersed 

 for 20 m. in a weak solution of sugar, either absorb the phos- 

 phate very slowly or are acted on by it very slowly. On the 

 other hand, glands, however they may have been treated, seem 

 easily to permit the subsequent 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 potas- 

 sium for 48 hrs. — of sulphate of potassium for 24 hrs. — and of 

 the chloride of potassium for 25 hrs. — on being placed in a 

 solution of one part of carbonate of ammonia to 218 of water, 

 had their glands immediately blackened, and after 1 hr. their 

 tentacles somewhat inflected, and the protoplasm aggregated. 

 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 this strength placed on the discs of leaves 

 do not cause any inflection ; and that when two days afterwards 

 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 the 

 leaves in the solution of camphor, but this produced no effect. 



* See Dr. M. Traiibe's curious By allowing a precipitation of 

 experiments on the production of sulphate of barium to take place 

 artificial cells, and on their per- at the same time, the membrane 

 meability to various salts, de- becomes "infiltrated" with this 

 scribed in his papers : " Experi- salt ; and in consequence of the 

 mente zur Theorie der Zellenbil- intercalation of molecules of sul- 

 dung und Endosmose," Breslau, phate of barium among those of 

 .1860; and " Experimente zur the gelatine precijDitate, the mole- 

 physicalischen Erklarung der Bil- cular interstices in the membrane 

 dung der Zellhaut, ihres AVachs- are made smaller. In this altered 

 thums durch Intussusception," condition, the membrane no longer 

 Breslau, 1874. These researclies allows the passage through it of 

 perhaps explain my results. Dr. either sulphate of ammonia or 

 Traube commonly employed as a nitrate of barium, though it re- 

 membrane the precipitate formed tains its permeability for water 

 when tannic acid comes into con- and chloride of ammonia, 

 tact with a solution of gelatine. 



