38 



COLD. 

 TABLE A. 



Mr. Blodgett gives an excellent table of the tem- 

 perature of the principal wine districts of this 

 country. (See Table B. p. 39.) 



6. It has been shown that heat is a great stim- 

 ulus to vegetable life. Cold^ on the other hand, 

 diminishes the activity of plants. At certain sea- 

 sons of the year a sudden fall in the temperature 

 produces in some kinds of vegetation disease and 

 death. If a frost occurs late in the spring, when 

 all the organs of the tree are performing their work 

 with great rapidity, the leaves and all those soft 

 parts which are filled with fluid become black and 

 stained, and lose their vitality. The green portions 

 of a tree are made up of cells, whose membraneous 

 \valls are very thin. On the contrary, those of the 

 wood are very thick ; but this varies according 

 to their age. When the juice contained in the 

 former, or young cells, has become frozen, it ex- 



