48 DEVELOPMENT GKOWTH SIZE. [BOOK i. 



and even as much as from four to five inches per day. 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 -g-o-g- of an inch in diameter, and it is probable they are 

 nearer the 4-^, it may be estimated to have consisted,, when 

 full grown, of about 47,000,000,000 cellules; so that, sup- 

 posing it to have gained its size in the course of twelve hours, 

 its cells must have developed at the rate of near 4,000,000,000 

 per hour, or of more than sixty-six millions in a minute. 

 This can be compared to nothing except the effect of liberat- 

 ing gas among mucus, and seems to be irreconcilable with 

 any other kind of development (see page 27), unless it is 

 assumed that in such cases cells are originally in a state of 

 violent compression, from which they spring up when the 

 pressure is removed. 



Cellular tissue grows for a long time after its generation, 

 and hence the bulk of a given part may be much increased 

 without the addition of any new elementary organs. Link 

 states that in the branch of a Pelargonium cucullatum, about 

 1 line in diameter, he found the larger cells -^ l - of a line 

 broad, while in an older branch of the same plant, 2 lines in 

 diameter, the larger cells were -nr of a line broad ; hence it 

 was evident that the growth of the branch depended upon 

 the growth of the individual cells. 



The bladders of cellular tissue are always very small, but 

 are exceedingly variable in size. The largest are generally 

 found among Cucurbits, or in pith, or in aquatic plants ; and 

 of these some are as much as the -> of an inch in diameter ; 

 the ordinary size is about the -j-^-g- or the 3-^, and they are 

 sometimes not more than the 1 \, . Kieser has computed 

 that in the garden pink more than 5100 are contained in half 

 a cubic line. 



Cellular tissue is found in two essentially different states, 

 the membranous and the fibrous. 



