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Show 382 PINGUICULA VULGARIS. CHAP. XVI. two or three days much reduced in size, rounded, rendered more or less colourless and transparent, and so much softened that they fell to pieces on the ~light~st touch. !n only one instance was a very minute particle completely dissolved, and this occurred within 48 hrs. \Vhen only a small amount of secretion was excited, this was generally absorbed in from 24 hrs. to 48 hr~. · the 0' lands being 1 eft dry. But when the supply ot secretion ~as co~ious, round either a single rather large bit of meat or round several small bits, the glands did not become dry ~ntil six or seven days had elapsed. The most rapid case of absorption observed by me was when ~ small drop of an infusion of raw meat was placed on a leaf, for the glands here became almost dry in 3 hrs: 20 m. Glands excited by small particles of meat, and which .ha.ve quickly absorbed their ?wn secretion beO'in to secrete again In the course of seven or mght ' 0 . days from the time when the meat was given them. (3) Three minute cubes of tough cartiluqe from the leg- bone of a sheep were laid on a leaf. After 10 brs. 30m. some acid secretion was excited, but the cartilage appeared little or not at all affected. After 24 hrs. the cubes wore rounded and much reduced in size; after 32 hrs. they ~ere softened to the centre, and one was quite liquefied; after 35 hrs. mere traces of solid cartilage were left ; and after 48 hrs. a trace could still be seen through a lens in only one of the three. After 82 hrs. not only were all three cubes completely liquefied, but all the secretion was absorbed and the gland~ left dry. (4) Small cubes of albumen were placed on a leaf; in 8 hrs. feebly acid secretion extended to a distance of nearly Yo of an inch round them, and the angles of one cube were rounJed. After 24 hrs. the angles of all the cubes were rounded, and they were rendered throughout very tender; after 30 hrs. the secretion began to de.crease, and after 48 hrs. the glands were left dry; but very minute bits of albumen were still left undissolved. (5) Smaller cubes of albumen (about 5~ or -r}0 of an inch, · 508 or · 423 mm.) were placed on four glands ; after 18 hrs. one cube was completely dissolved, the others being much reduced in size softened and transparent. After 24 hrs. two of the cubes w' ere comp' letely diEsolved, and already the secretion on these glands was almost wholly absorbed. After 42 hrs. the two other cubes were completely dissolved. These four glands began to secrete again after eight or nine days. (6) Two large cubes of albumen (fully •io of an inch, 1·27mm) wore placed, one near the midrib and the other near the margm CHAP. XVI. SECRETION, ABSORPTION, DIGESTION. 383 of a leaf; in 6. hrs. ~hero was much secretion, which after 48 brs. a~c~u]ated 1n a little pool round tho cube near the margin. This cube was much more dissolved than that on the blade of th.e leaf; so that after three days it was greatly reduced in size With all the angles rounded, but it was too laro·e to bo wholl' dissolved. Tho secretion was partially absorbed ~ftor four day{ 'rhe c~be. on the blade was much Jess reduced, and the gland~ on whiC~ It. reste~ began to dry after only two days. (7) lt1. b~~n exmtes less secretion than does meat or albumen. Several. tnals were made, but I will give only three of them. Two min~1te shre~s were placed on some glands, and in 3 hrs. 45 m. theu secretwn was plainly increased. The smaller shred of the two was completely liquefied in 6 hrs. 15m., and the other in. 24 hrs.; but even after 48 hrs. a few granules of fibrin could still be seen through a lens floating in both drops of secretion. After. 56 hrs. 30m. these ~ranul~s were completely dissolved. A thud shred was placed In a httle pool of secretion within the margin of a leaf where a seed had been lying ~nu this was complet~ly dissolved in the course of 15 hrs. 30 ~. (8) Five very small bits of gluten were placed on a leaf and they ~xcited so m~ch ~ecretion that one of the bits giided clown mto the marg1nal furrow. After a day all five bits seemed much reduced in size, but none were wholly dissolved. On the third day I pushed two ~f them, which had begun to dry, on to fresh glands. On the fourth day undissolved traces of three ou~ of t~1e five bits could still be detected, the other two having quite disappeared;. but I am doubtful whether they had really been completel;y dissolved. Two fresh bits were now placed, one near the ~Iddle and the other near the margin of another loaf; both exCI~ed an ext1~aordinary amount of St!Cretion; that near the margin had a httle pool formed round it, and was much more reduced in size than that on the blade, but after fou7 days was not completely dissolved. Gluten, therefore, exmtes the glands greatly, but is dissolved with much difficulty ex~ctly as in the case ?f Drosera. I regret that I did not t;; th~s su b~tance after haVIng been immersed in weak hydrochloric aCid, as It would then probably have been quickly dissolved. .C9) A small square thin piece of pure gelatine, moistened ~Ith. water, was placed on a leaf, and excited very little secretwn In 5 hrs. 30 m., but later in the day a greater amount. A~ter 24 Ius. the whole square was completely liquefied; and this would not have occurred had it been left in water. The liquid was acid. (10) Small particles of chemically prepared casein. excited |
