72 DROSERA ROTUNDIFOLIA. [Cuap. VI. 
glands of 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 secretion 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 evidence. 
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 affect 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 were 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 
secretion 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 them was likewise strongly acid. As raw meat 
* (In the ‘ Proceedings of the Royal _ing secretion, and gives evidence that 
Society,’ 1886, No. 240,Gardiner has _ the secretion results from the break 
described the changes which goon in ing downof the protoplasmic reti- 
the glands of Drosera dichotoma dur- _ culum of the gland-cell.—F. D.] 
