On three other occasions eight leaves were strongly excited with albumen moistened with saliva; they were then cut off, and allowed to soak for several hours or for a whole day in a few drops of glycerine.  Some of this extract was added to a little hydrochloric acid of various strengths (generally one to 400 of water), and minute cubes of albumen were placed in the mixture.* In two of these trials the cubes were not in the least acted on; but in the third

* As a control experiment bits of albumen were placed in the same glycerine with hydrochloric acid of the same strength; and the albumen, as might have been expected, was not in the least affected after two days. [page 98]

the experiment was successful.  For in a vessel containing two cubes, both were reduced in size in 3 hrs.; and after 24 hrs. mere streaks of undissolved albumen were left.  In a second vessel, containing two minute ragged bits of albumen, both were likewise reduced in size in 3 hrs., and after 24 hrs. completely disappeared.  I then added a little weak hydrochloric acid to both vessels, and placed fresh cubes of albumen in them; but these were not acted on.  This latter fact is intelligible according to the high authority of Schiff,* who has demonstrated, as he believes, in opposition to the view held by some physiologists, that a certain small amount of pepsin is destroyed during the act of digestion.  So that if my solution contained, as is probable, an extremely small amount of the ferment, this would have been consumed by the dissolution of the cubes of albumen first given; none being left when the hydrochloric acid was added.  The destruction of the ferment during the process of digestion, or its absorption after the albumen had been converted into a peptone, will also account for only one out of the three latter sets of experiments having been successful.

Digestion of Roast Meat.—­Cubes of about 1/20 of an inch (1.27 mm.) of moderately roasted meat were placed on five leaves which became in 12 hrs. closely inflected.  After 48 hrs.  I gently opened one leaf, and the meat now consisted of a minute central sphere, partially digested and surrounded by a thick envelope of transparent viscid fluid.  The whole, without being much disturbed, was removed and placed under the microscope.  In the central part the transverse striae on the muscular fibres were quite distinct; and it was

* ‘Leons phys. de la Digestion,’ 1867, tom. ii. pp. 114-126. [page 99]

interesting to observe how gradually they disappeared, when the same fibre was traced into the surrounding fluid.  They disappeared by the striae being replaced by transverse lines formed of excessively minute dark points, which towards the exterior could be seen only under a very high power; and ultimately these points were lost.  When I made these observations, I had not read Schiff’s account* of the digestion of meat by gastric juice, and I did not understand the meaning of the dark points.  But this is explained in the following statement, and we further see how closely similar is the process of digestion by gastric juice and by the secretion of Drosera.