PRESSURE OF SQUASH-SAP. 221 



stantly multiplying by subdivision until their number was 

 many billions, notwithstanding the enormous pressure under 

 which they were forced to develop. This growth was possi- 

 ble only because life is a molecular force and exerted its 

 almost irresistible power over an immense surface of cell 

 membrane. 



Scarcely less astonishing than the mechanical force exhib- 

 ted was the ability of the tissues of the squash to resist 

 chemical changes and. the attacks of mould, when the rind 

 was injured by bruises or cuts. Whenever fresh-growing 

 cells were exposed to the action of the air, they immediately 

 began to form a regular periderm of cork, precisely similar 

 in appearance and structure to that produced upon the cork- 

 oak, the elm, and other trees. 



The form of the squash can hardly be described, but may 

 be seen in the drawings which show the upper and under 

 sides. The weight was forty-seven pounds and a quarter, 

 and when opened the rind was found to be about three inches 

 thick and unusually hard and compact. The internal cavity 

 corresponded in general form to the exterior, but was very 

 small, and nearly filled with fibrous tissue and plump and 

 apparently perfect seeds in about the normal number. A 

 squash of the same variety, grown in the field by Messrs. 

 Russell Brothers, in North Hadley, weighed one hundred and 

 twenty-three pounds. Its form was ovoid, but flattened as if 

 by its own weight, and the cavity within had a capacity of 

 about sixteen quarts. 



Two vines having been started together in our experimen- 

 tal bed, it was decided to apply a mercurial gauge (such as 

 will be described in another place) to the neck of one cut off 

 at the ground, when the vine was about eight wrecks old and 

 had a length of twelve feet. The result was quite surpris- 

 ing, greatly surpassing anything heretofore recorded, so far 

 as w T e are aware, concerning the pressure exerted by the sap 

 of an herbaceous plant, the maximum force with which the 

 root of the squash exuded the water absorbed by it being 

 equal to a column of water 48.51 feet in height. The gauge 

 was applied about noon, August 27th. At 2 p. m., August 

 28th, the temperature of the pit being 86° Fahrenheit, the 

 pressure on the gauge equalled 31.70 feet of water. 



