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 Systime de Chimie Oi'ganique, 

 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 covu'se 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, v^'ith great rapidity. I 

 have seen Lupinus 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 

 ^ J-Q of an inch in diameter, and I suspect they are nearer the 

 ^00, 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 



