152 ■ HEAT. 



was the cause of their destruction. The tissues being filled 

 with sap, it was supposed that when this was frozen, the con- 

 sequent expansion ruptured the tissues, and unfitted them for 

 any longer performing their functions. This very plausible 

 theory, it seems has been entirely set aside by some, but by 

 others it is still considered a concurrent cause in the destruc. 

 tion of some vegetables at least. 



The following is compiled from an article in the 39th vol. 

 of Silliinan's American Journal of Science, from the pen of 

 Prof. Lindley. 



225. "Mr. Goeppert, denies that the laceration of tissue, 

 takes place in freezing, and asserts that cold operates in de- 

 stroying the vitality of plants, which is followed by a change 

 in the chemical constitution of their juices." 



Prof. Morron has given the following conclusions as the 

 result of his inquiries. 



1. "That no organ whatever, is torn by the action of frost, 

 except in very rare cases, when the vesicles of cellular tissue 

 give way, but that the vesicles of plants are separated from 

 each other without laceration. 2. That neither the chloro- 

 phyll, the nucleus of cells, elementary fibre, amylaceous mat- 

 ter, raphides, nor the various crystals contained in vegetable 

 tissue, undergo any alteration, unless perhaps in the case of am- 

 ylaceous substances, which, in some cases are converted into su- 

 gar, no doubt in consequence of the action of some acid, formed 

 by the decomposition of the organic parts. 3. That the action 

 of frost, operates separatel}' upon each individual elementary 

 organ, so that a frozen plant contains as many icicles, as 

 there are cavities containing fluid ; the dilatation thus pro- 

 duced not being sufficient to burst the sides of the cavities. 

 4, That such dilatation is principally owing to the separation 

 of the air contained in the ^^ater. 5. That this disengage- 

 ment of air froai water, during the act of congelation, is the 

 most injurious of all the phenomena attendant upon freezing; 

 introducing gaseous matter into organs not intended to elab- 

 orate it, and bringing about the first stage in a decomposition, 

 of the sap and the matter it precipitates; so tliat with a 

 thaw, commences a new chemical action, destructive of veg- 

 etable life, 6. 1 hat the expansion of the cells and aquiferous or- 

 gans, drives a great quantity of water into the air cells and air 

 vessels, so that the apparatus intended to convey liquid only, 

 contains water and air, while that which is naturally a vehicle 

 for air, conveys water. Such an inversion of functions, must ne- 

 cessarily be destructive to vegetable life, even if death were 

 not produced in frozen plants, by the decomposition of their 



