Ouar.XVIL SUMMARY ON ABSORPTION. 421 
irregularly aggregated masses; others were still colourless, 
though their utricles were shrunk; but the greater number 
were not much affected. This was a good instance of how 
unequally the glands on the same bladder are sometimes 
affected, as likewise often occurs with plants growing in fou] 
water. Two other summits were treated with a solution which 
had been kept during several days in a warm room, and their 
glands were not at all affected when examined after 21 hrs. 
A weaker solution of one part of urea to 487 of water was next 
tried on six summits, all carefully examined before being irrigated. 
The first was re-examined after 8 hrs. 30 m., and the glands, 
including the spherical ones, were brown; many of the oblong 
glands having their primordial utricles much shrunk and in- 
cluding granules. The second summit, before being irrigated, 
had been somewhat affected by the surrounding water, for the 
spherical glands were not quite uniform in appearance; and a 
few of the oblong ones were brown, with their utricles shrunk. 
Of the oblong glands, those which were before colourless, be- 
came brown in 3 hrs. 12 m. after irrigation, with their utricles 
slightly shrunk. The spherical glands did not become brown, 
but their contents seemed changed in appearance, and after 
23 hys. still more changed and granular. Most of the oblong 
glands were now dark brown, but their utricles were not 
greatly shrunk. The four other specimens were examined after 
8 hrs. 80 m, after 4 hrs., and 9 hrs.; a brief account of their 
condition will be sufficient. The spherical glands were not 
brown, but some of them were finely granular. Many of the 
oblong glands were brown; and these, as well as others which 
still remained colourless, had their utricles more or less shrunk, 
some of them including small aggregated masses of matter. 
Summary of the Observations on Absorption —From 
the facts now given there can be no doubt that the 
variously shaped glands on the valve and round the 
collar have the power of absorbing matter from weak 
solutions of certain salts of ammonia and urea, and 
from a putrid infusion of raw meat. Prof. Cohn 
believes that they secrete slimy matter; but I was 
not able to perceive any trace of such action, ex- 
cepting that, after immersion in alcohol, extremely 
fine lines could sometimes be seen radiating from theiz 
