CHAP. I. 
CELLULAR TISSUE. 
9 
ence to this principle. He further supposes, that each such 
granule is one of the elementary molecules of the membrane of 
the tissue, in a state of developement. Those who are curious 
to know the exact nature of these speculations, should consult 
the memoir of Turpin, in the Memoires du Museum, vol. xviii. 
p. 212., and Raspail's Nouveau Systeme de Chimie Oryanique, 
p. 83. The mode in which cellular or any other tissue is really 
formed has been clearly made out in two separate cases. 
Amici found that the new tubes of Chara appear like young- 
buds, from the points or axils of pre-existing tubes, an ob- 
servation which has been confirmed by Slack. It has been 
distinctly proved by Mirbel that the same thing occurs in the 
case of Marchantia polymorpha. That learned botanist, in 
the course of his enquiries into the structure of this plant, 
may be said to have assisted at the birth of its cellular tissue ; 
and he found that in all cases one tube or utricle generated 
another, so that sometimes the membranes of newly-formed 
tissue had the appearance of knotted or branched cords. He 
satisfied himself that new parts are formed by the generative 
power of the first utricle, which spontaneously engenders others 
endowed with the same property. 
The bladders develope, in some cases, with great rapidity. I 
have seen Lupin us polyphyllus grow in length at the rate of an 
inch and a half a day. The leaf of Urania speciosa has been 
found by Mulder to lengthen at the rate of from one and a 
half to three and a half lines per hour, and even as much as from 
four to five inches per day. This may be computed to equal 
the developement of at least 4000 or 5000 bladders per hour. 
But the most remarkable instances of this sort are to be found 
in the mushroom tribe, which in all cases develope with sur- 
prising rapidity. It is stated by Junghuns, that he has known 
the Bovista giganteum, in damp warm weather, grow in a 
single night from the size of a mere point to that of a huge 
gourd. We are not further informed of the dimensions of this 
specimen; but supposing its cellules to be not less than the 
of an inch in diameter, and I suspect they are nearer the 
4^)0, it may be estimated to have consisted, when full grown, 
of about 47,000,000,000 cellules ; so that, supposing it to have 
gained its size in the course of twelve hours, its bladders must 
