Ouar. XV. THEIR POWER OF ABSORPTION. 345 
the species of Droseracee absorb various fluids or 
at least allow them readily to enter,* it seemed desir- 
able to ascertain how far the glands of other plants 
which are not specially adapted for capturing insects, 
had the same power. Plants were chosen for trial 
at hazard, with the exception of two species of saxi- 
frage, which were selected from belonging to a family 
allied to the Droseraceee. Most of the experiments 
were made by immersing the glands either in an in- 
fusion of raw meat or more commonly in a solution of 
carbonate of ammonia, as this latter substance acts so 
powerfully and rapidly on protoplasm. It seemed also 
particularly desirable to ascertain whether ammonia 
was absorbed, as a small amount is contained in rain- 
water. With the Droseracex the secretion of a viscid 
fluid by the glands does not prevent their absorbing ; so 
that the glands of other plants might excrete super- 
fluous matter, or secrete an odoriferous fluid as a 
protection against the attacks of insects, or for any other 
purpose, and yet have the power of absorbing. I 
regret that in the following cases I did not try whether 
the secretion could digest or render soluble animal 
substances, but such experiments would have been 
difficult on account of the small size of the glands 
and the small amount of secretion. We shall see in 
the next chapter that the secretion from the glandular 
hairs of Pinguicula certainly dissolves animal matter. 
Stxifraga umbrosa.—The flower-peduncles and petioles of the 
leaves are clothed with short hairs, bearing pink-coloured glands, 
formed of several polygonal cells, with their pedicels divided hy 
partitions into distinct cells, which are generally colourless, but 
sometimes pink. The glands secrete a yellowish viscid fluid, by 
* The distjnction between true clearly understood: see Miiller’s 
absorption and mere permeation, ‘Physiology,’ Eng. translat. 1838 
or imbibition, is by no means vol. i. p. 280. 
