Ohap. XVII. SUMMAEY ON ABSOKPTION. 42l 



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 foul 

 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 437 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 hrs. 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 

 3 hrs. 30 m., after 4 hrs,, and 9 hrs. ; a brief account of their 

 condition will be suflBcient. 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. 



Sum7nary 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 their 



