72 DROSERA ROTUNDIFOLIA. [Cdap. VI. 



the disc are excited by the contact of any object, especially 

 of one containing nitrogenous matter, the outer tentacles 

 and often the blade become inflected; the leaf being thus 

 converted into a temporary cup or stomach. At the same 

 time the discal glands secrete ' more copiously and the secre- 

 tion becomes acid. Moreover, they transmit some influence 

 to the glands of the exterior tentacles, causing them to pour 

 forth a more copious secretion, which also becomes acid or 

 more acid than it was before. 



As this result is an important one, I will give the evi- 

 dence. The secretion of many glands on thirty leaves, which 

 had not been in any way excited, was tested with litmus 

 paper; and the secretion of twenty- two of these leaves did 

 not in the least afiFect the colour, whereas that of eight caused 

 an exceedingly feeble and sometimes doubtful tinge of red. 

 Two other old leaves, however, which appeared to have been 

 inflected several times, acted much more decidedly on the 

 paper. Particles of clean glass wore then placed on five of 

 the leaves, cubes of albumen on six, and bits of raw meat on 

 three, on none of which was the secretion at this time in the 

 least acid. After an interval of 24 hrs., when almost all the 

 tentacles on these fourteen leaves had become more or less 

 inflected, I again tested the secretion, selecting glands which 

 had not as yet reached the centre or touched any object, and 

 it was now plainly acid. The degree of acidity of the secre- 

 tion varied somewhat on the glands of the same leaf. On 

 some leaves, a few tentacles did not, from some unknown 

 cause, become inflected as often happens; and in five in- 

 stances their secretion was found not to be in the least acid ; 

 whilst the secretion of the adjoining and inflected tentacles 

 on the same leaf was decidedly acid. With leaves excited by 

 particles of glass placed on the central glands, the secretion 

 which collects on the disc beneath them was much more 

 strongly acid than that poured forth from the exterior 

 tentacles, which were as yet only moderately inflected. When 

 bits of albumen (and this is naturally alkaline), or bits of 

 meat were placed on the disc, the secretion collected beneath 



[In the ' Proceodlngs of the Injt seoretlon, nnd (flve evidence 



Royal Society,' 188(J, No. 240, that the secretion reHultH from 



Gardiner baa described the the breakhiK down of the proto- 



chnnsefl which go on in the plaHnilc reticulum of the gland- 



glands of Droacra dichotoma dur- celL F. D.] 



