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Show 422 UTRICULAR! A NEG LEOTA. CI-IAr. XVII. surfaces. The glands are variously affected by absorption ; they often become of a brown colour ; so1netimes th y contain very :fine granules, or moderately sized o-rains, or irregularly aggregated little masses; somefilnes the nuclei appear to have increased in size ; the 1)fi1nordial u tricles are generally more or less shrunk and someti1nes ruptured. Exactly the same changes n1ay be observed in the glands of plants growing a.nd flourishing in foul water. The spherical glands are generally affected rather differently fro1n the oblong and two-armed ones. The former do not so commonly become brown, and are acted on more slowly. We may therefore infer that they differ somewhat in their natural functions. It is remarkable how unequally the glands on the bladders on the same branch, and even the glands of the same kind on the same bladder, are affected by the foul water in which the plants have grown, and by the solutions which were en1ployed. In the former case I presume that this is due either to little currents bringing matter to some glands and not to others, or . to unknown differences in their constitution. When the glands on the same bladder are differently affected by a solution, we may suspect that some of them had previously absorbed a small amount of matter from the water. However this may be, we have seen that the glands on the same leaf of Drosera are sometimes very unequally affected, more especially \Vhen exposed to certain vapours. If glands which have already become brown, with their primordial ntricles shrunk, are irrigated with one of the effeetive solutions, they are not acted on, or only slightly and slowly. If, however, a gland contains merely a few .coarse granules, this does not · prevent a solution from .acting. I have never seen CHAP. XVII. SUMMARY ON ABSORPTION. 423 any appearance making it probable that glands which have ~een strongly affected by absorbing matter of any k1nd are capable of recovering their pristine, colourless, and homogeneous condition and of reO'ain- I. ng t h e power of absorbing. ' 0 From the nature of the solutions which were tried I presume t~at nitroge~ is absorbed by the glands~ but the modified, brownish, more or less shrunk, and aggregated contents of the oblong glands were never seen by me or by my son to undergo those spon- . taneous changes of form characteristic of protoplasm. On ~he other hand, the contents of the larger sphencal gl~nds often separated into small hyaline glo?ules or Irregularly shaped masses, which changed theu. forms very slowly and ultimately coalesced, forming a central shrunken mass. Whatever may be the nature of the contents of the several kinds of glands, after they have been acted on by foul water or by one of the nitrogenous solutions, it is probable that the matter thus generated is of service to the plant, and· is ultimately transferred to other parts. The glands apparently absorb more quickly than do the q uadrifid and bifid processes ; and on the view above maintained, namely that they absorb matter from putrid water occasionally emitted from the bladders, they ought to act more quickly than the processes; as these latter remain in permanent contact with captured and decaying animals. Finally, the conclusion to which we are led by the foregoing experiments and observations is that the bladders have no power of digesting animal matter, though it appears that the quadri:fids are somewhat affected by a fresh infusion of raw meat. It is certain that the processes within the bladders, and the glands outside, absorb matter from salts of |