196 Prof. J. Le Conte on the Freezing of Vegetables. 
but sensible, quantity of fluid could, likewise, be expressed from 
any portion of the pith, so as to appear on the cut surface, and 
‘which would disappear as soon as the compressing force was 
withdrawn. It was also found, that fluid appeared at the trans- 
verse cut surface of the liber, when pressed against the subjacent 
wood at the extremities. It was hoped, that the application of 
the foregoing tests, would enable us to ascertain with considera- 
ble certainty, whether the juices of these portions of the plant 
co eadily frozen, independently of any light which mir _ 
croscopic examination might throw upon the question. 
Experiment No. 1.—February 2nd, 1851, 1 o’clock, p.m. ; the 
‘temperature of the room being 42° Fahr., and that of the freezin 
mixture varying, during the experiment, from 2° to 5° Fahr. 
Wit iew of excluding the direct contact of the frigorific 
mixture, the internode of elder was inserted into a water tight 
tinned sheet-iron case or cylinder, of nearly the same diameter as 
the stalk,—the whole was plunged vertically, and in the natural 
growing position, into the freezing mixture; about seven-eights 
of the internode being below the surface.. At the expiration of 
two hours, the stalk was removed from the case for examination. 
The extremity which was above the cold mixture, was found to. 
be surrounded by a thin transparent coating of ice. The flui 
seemed to have been forced up along the inner bark and the suc- 
culent zone surrounding the pith, by the contraction which took 
place in the part of the stem below the mixture, before congela- 
tion supervened. The lower extremity was found to be quite 
free from external ice, and appeared comparatively dry. The 
fluids of the bark, as well as those of the succulent zone around 
the pith, were obviously congealed. The frozen condition was 
rendered evident, by slicing the bark longitudinally with a shatp 
knife ,—the ice could be scraped off with the edge of the instru- 
ment. In like manner, small masses of solidified juice could be 
detached from the succulent zone as well as the pith. 
Inder the microscope,—when a transverse section was made 
the glass plate on which they are placed for examination, should 
be artificially cooled. 
