300 Observations upon the effects of Frost, 



published some exceedingly interesting observations upon this 

 subject. Like M. Gceppert, he denies the truth of the state- 

 ment generally made, that frost produces death in plants by 

 bursting their vessels ; 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 tissue give way, but that the vesicles of plants 

 are separated from each other by frost without laceration. 2. That 

 neither the chlorophyll, the nucleus of cells, elementary fibre, 

 amylaceous matter, raphides, nor the various crystals contained in 

 vegetable tissue, undergo 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, formed by 

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

 operates separately upon each individual elementary organ, so that 

 a frozen plant contains as many icicles as there are cavities con- 

 taining fluid ; the dilatation thus produced not being sufficient to 

 burst the sides of the cavities. 4. That such dilatation is prin- 

 cipally owing to the separation of the air contained in the water. 



5. That this disengagement of air by water during the act of con- 

 gelation, is the most injurious of all the phenomena attendant upon 

 freezing : introducing gaseous matter into organs not intended to 

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

 of the sap and the matters it precipitates ; so that with a thaw 

 commences a new chemical action destructive of vegetable life. 



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

 great quantity of water into the air-cells, and air-vessels, so that 

 the apparatus intended to contain 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 

 vegetable 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. 



