three times daily. These did not in the least delay the process; for,
after 48 hrs., the cubes were completely dissolved on all three leaves.
On the third day the leaves began to re-expand, and on the fourth day
all the fluid was absorbed.
Experiment 7. Small cubes of albumen were put on two leaves, and minute
drops of hydrochloric acid, of the strength of one part to 437 of
water, were added two or three times. This did not in the least delay,
but seemed rather to hasten, the process of digestion; for every trace
of the albumen disappeared in 24 hrs. 30 m. After three days the leaves
partially re-expanded, and by this time almost all the viscid fluid on
their discs was absorbed. It is almost superfluous to state that [page
95] cubes of albumen of the same size as those above used, left for
seven days in a little hydrochloric acid of the above strength,
retained all their angles as perfect as ever.
Experiment 8. Cubes of albumen (of 1/20 of an inch, or 2.54 mm.) were
placed on five leaves, and minute drops of a solution of one part of
carbonate of soda to 437 of water were added at intervals to three of
them, and drops of carbonate of potash of the same strength to the
other two. The drops were given on the head of a rather large pin, and
I ascertained that each was equal to about 1/10 of a minim (.0059 ml.),
so that each contained only 1/4800 of a grain (.0135 mg.) of the
alkali. This was not sufficient, for after 46 hrs. all five cubes were
dissolved.
Experiment 9. The last experiment was repeated on four leaves, with
this difference, that drops of the same solution of carbonate of soda
were added rather oftener, as often as the secretion became acid, so
that it was much more effectually neutralised. And now after 24 hrs.
the angles of three of the cubes were not in the least rounded, those
of the fourth being so in a very slight degree. Drops of extremely weak
hydrochloric acid (viz. one part to 847 of water) were then added, just
enough to neutralise the alkali which was still present; and now
digestion immediately recommenced, so that after 23 hrs. 30 m. three of
the cubes were completely dissolved, whilst the fourth was converted
into a minute sphere, surrounded by transparent fluid; and this sphere
next day disappeared.
Experiment 10. Stronger solutions of carbonate of soda and of potash
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