70 REPORT—1845. 
precisely those for vegetation, 2. Many plants with hard perisperms, as the Phyte- 
lephas macrocarpa, the Phoenix dactylifera, and species of Bactris, Cocos and Astro- 
caryum, germinate without consuming any appreciable quantity of tbe perisperm. 
3. The quantity of carbonic acid obtained by Saussure varied not according to the 
number, but according to the mass of the seeds, proving that it arose from the decom- 
position of the starch as a chemical process, and not from the growth of the embryo 
as a process of life, 4. De Saussure found that the relation between the oxygen con- 
sumed and the carbonic acid gas given out, was different in different plants for the 
same quantity of the latter, which ought to be constant if the theory of oxidation or 
combustion during germination be true. 5, Boussingault found that the changes 
supposed to be peculiar to germination went on in the perisperm after the young 
plant had developed its radicle and plumule, and was capable of an independent exist- 
ence. 6. The changes which take place in the chemical composition of the perisperm 
of the seed during germination can be artificially produced by mixing starch, diastase, 
&c. together and exposing them to the action of the atmosphere. This theory modi- 
fies the view of the use of the albumen or perisperm. It is not deposited essentially 
for the nourishment of the young plant. In some cases it is an organ of support, and 
bears the same relation to the embryo as the wood of a branch to the buds upon it. 
Viewing it morphologically, it might be considered the analogue of the tegmenta of 
the buds; as they consisted of aborted leaves, so the albumen or perisperm consisted 
of embryos aborted in their earliest stages of development. 
On the Phytelephas Macrocarpa (Vegetable Ivory or Tagua Plant). 
By E. Lanxester, M.D., F.R.S, 
The author brought this plant under the notice of the Section, as he was enabled 
to present a drawing of a young plant, which was now growing in the garden of 
Messrs. Loddiges of Hackney. A fruit also of this plant existed in the British Mu- 
seum, of which a drawing was exhibited. This plant had been placed in the natural 
order Typhine by Bonpland and Humboldt; with Pandanee by Brown; with Cy- 
clanthacee by Lindley. The fruit is of the size of a man’s head, and the tree is called 
by the Spaniards Negro-head. A remarkable point in the ceconomy of this plant 
was, that the horny albumen of the seed appeared to undergo no change during 
the process of germination. In the plant at Loddiges’, which was now five years old, 
the seed still remained on the surface of the soil, apparently as hard as ever, In 
germination, the young embryo was carried down by a rhizoma an inch or more Jong 
into the earth, and commenced growing at that point. 
The perisperms of other palms, as the species of Bactris, of Cocos, and of the 
Phenix dactylifera, also undergo but little change during germination. The peri- 
sperm of a species of Astrocaryum in British Guiana is stated by Sir Robert Schom- 
burgk to be as hard as that of Phytelephas. The structure of the tissue of the seed 
is remarkable. The walls of the cells are very thick, and in their early stages porous ; 
the pores between the cells are at last closed, and the pores form club-shaped cavities 
leading out of the cells. Cooper, in his illustration of the microscopic structure of 
these cells, has drawn a line running between these club-shaped cayities, but this arises 
from a tube lying underneath, and has no connection with the termination of the 
pores, The cells by the resorption of their walls become converted into tubes, , The 
tubes under the microscope appear to contain globules of oil, Chemical analyses of 
the seeds had been made by Payen, Connell and Baumhauer. A more accurate ana- 
lysis was made, at the author’s request, by Dr. Percy of Birmingham. The result of 
this analysis was as follows :— 
Carbon, ressecrrerevevcensceseenss 4439 
Hydrogen ..jesesserererereeees 6°63 
Oxygen srerercenssntepercsreeee FCO 
NIGVOGON sali rvasdechsosarannes cits cle 
100-00 
In drying 12-64 per cent. of water was dissipated. The ash contained sulphuric, 
hydrochloric, phosphoric and carbonic acids in combination with potassa, lime and 
oxide of iron. The phosphoric acid was partly combined with the potassa. The iron 
was probably introduced in filing the perisperm for chemical examination. 
