DESTRUCTION OF PLANTS BY FROST. 



time ago, an excellent abstract of their views, accompanied bj- some conclusions of his 

 own, in the following article, which will repay perusal. Ed. 



" In considering the various circumstances alluded to in this paper, I was naturally led 

 to inquire into the exact manner in which the death of plants is caused by cold. Very 

 little, however, is to be learned upon this subject from the writings of physiologists. 



" The common opinion is, that frost acts mechanically upon the tissue of plants, by ex- 

 panding the fluid they contain, and bursting the cells or vessels in which it is enclosed. 



"M. Goeppert, of Breslau, in a paper originally read at the meeting of German natu- 

 ralists, at Leipsig, in 1829, briefly abstracted in Okcn^s Isis for 1830, p. 497, and trans- 

 lated in the Edinburgh Journal of Natural and Geological Science for 1831, p. 180, de- 

 nies that this supposed laceration of vegetable tissue by frost, takes place. He is repre- 

 sented to have stated, that the changes which plants undergo, when they are killed by 

 cold, do not consist in a bursting of their vessels or cells, but solely in an extinction of 

 vitality, ■which is followed by changes in the chemical composition of their juices. 



" Professor Morren, of Liege, in a paper printed in the fifth volume of the Bulbtin de 

 I' jicadcmie RoyaU de Bruxellcs, has published some exceedingl)'^ interesting observa- 

 tions upon this subject. Like M. Goeppert, he denies the truth of the statement general- 

 ly made, that frost produces death in plants by bursting their ves.sels; and he assigns the 

 effect to other causes. His more important conclusions are, 1. That no organ, whatever, 

 is torn by the action of frost, except in very rare cases, when the vesicles of cellular tis- 

 sue give way, but that the vesicles of plants are separated from each other by frost, with- 

 out laceration. 2. That neither the chlorophyll, the nucleus of cells, elementary fibre, 

 amylaceous matter, raphides, nor the various crystals contained in vegetable tissue, un- 

 dergo any alteration, unless, perhaps, in the case of amylaceous matter, which, in some 

 cases, is converted into sugar, no doubt, in consequence of the action of some acid, form- 

 ed by the decomposition of the organic parts. 3. That the action of frost operates se- 

 parately upon each individual elementary organ, so that a frozen plant contains as many 

 icicles as there are cavities containing fluid ; the dilitation thus produced not being suffi- 

 cient to burst the sides of the cavities. 4. That such dilitation is principally owing to 

 the separation of the air contained in the water. 5. That this disengagement of air by 

 water, during the act of congelation, is the most injurious of all the phenomena 

 attendant upon freezing: introducing gaseous matter into the organs not intended to ela- 

 borate it, and bringing about the first stage in the decomposition of the sap and the matters 

 it precipitates; so that with a thaw commences a new chemical action, destructive of ve- 

 getable life. 6. That the expansion of the cells, and aquiferous organs, drives a great 

 quantit}' of water into the air-cells and air-vessels, so that the apparatus intended to con- 

 tain liquid only, contains water and air, while that which is naturally a vehicle for air, 

 conveys water. Such an inversion of functions must necessarily be destructive to vege- 

 table life; even if death were not produced in frozen plants by the decomposition of their 

 juices, the loss of their excitability, and the chemical disturbance of all their contents. 



" Professor Morren's observations were made upon various plants frozen in the spring 

 of the present year, having been exposed to a temperature of — 4*^ to -\-9° Fahrenheit. 

 One of his statements I give in his own words. ' In the parenchyma of many plants, and 

 especially in that of succulent fruits, it is easy to ascertain what modifications are caused 

 by frost in the internal organs of plants. If a frozen apple is opened, it is obvious that 

 the ice is not a continuous mass, but that it is a collection of a multitude of little micro- 

 pical icicles. Lender the microscope the fact becomes evident. We know how 

 hard some fruits become when frozen by this mosaic of icicles, especially pears 



