2 
ORGANOGRAPHY. 
BOOK I. 
mitive condition of vegetable tissue; although it has long 
been known as a substance existing in Algaceous plants, prior 
to the appearance of organization, as in Protococcus nivalis, 
&c. It has been found by Brongniart, Henslow, &c. in the 
form of a thin homogeneous membrane, applied to the cuticle 
of the leaves of some plants, and only separable after mace- 
ration ; it is probable that it constitutes the whole exterior 
surface of all plants, and that it is even drawn over the sacs 
which constitute hairs ; I have found it distinctly on the 
petals of Hydrotaenia meleagris (see Bot. Reg. 1838. misc. 
No. 128.), but its extreme tenuity and firm adhesion to the 
tissue below it renders it difficult to detect it; and there is 
no doubt that it occurs very generally in the interior of plants 
between their cells, filling up the intercellular spaces, and 
gluing together all the parts. Mold, with his usual skill, has 
shown that this substance is found so frequently, that we can- 
not refuse to acknowledge its presence as a constant fact. 
The Box, and the young annual shoots of Sambucus nigra, 
are especially noticed as well suited to show this structure ; 
it will be seen to form a considerable part of the mass of the 
albumen of Alstromeria salsilla, see fig. 2. c. where it is 3 
of an inch in diameter. Valentin has measured the thick- 
ness of the intercellular organic mucus in several instances, 
and gives the following table of the proportion betw'een it and 
the ceils of certain plants, calculated in Paris inches. 
Camellia Japonica 
Thickness of the 
intercellular mucus. 
- 0,000112 
Size of 
the cell. 
0,000675 
Proportion of the 
1st to the 2d. 
1 : 6,02 
Hoya carnosa 
- 0,000150 
0,000650 
1 
: 4,33 
Magnolia gran diflora 
- 0,000150 
0,000425 
1 
: 2,83 
Cestrum laurifolium 
- 0,000275 
0,001550 
1 
: 5,63 
Daphne Laureola - 
- 0,000390 
0,001000 
1 
: 2,56 
Finns Picea 
- 0,0004-50 
0,001200 
1 
: 2,66 
Aloe intermedia 
- 0,000775 
0,002100 
1 
: 2,71 
Aloe lingua 
- 0,000825 
0,002575 
1 
: 3,12 
Agave Americana - 
- 0,000850 
0,002375 
1 
: 2,79 
Meyen admits the fact of the presence of this intercellular 
mucus, but considers it a secretion from the sides of the cells. 
He particularly refers to its condition in the petiole of Beta 
cycla, in proof of the correctness of that view. 
