138 PLANT LIFE ON THE FARM. 



circular or irregular spots of brown decayed protoplasm. 

 The effects of frost and the reason it kills have been 

 explained in a former page. Nothing, however, can be 

 advanced in explanation of the reasons why some plants of 

 the same species, like the different varieties of wheat, are so 

 much more tender than others. Death by the leaf is rarely 

 immediately fatal, because there are many leaves, and tljtfly 

 are not often all affected in the same way at the same time* ; 

 and, moreover, in the case of plants other than " annuals," 

 the fall and death of the leaves does not involve the death 

 of the plant, as before explained. Even in the case of 

 annuals, the life, like the nutritive matter, goes out of the 

 leaves only to enter the seed. 



Successor thus follows predecessor in one invariable 

 rhythm, and although the limits of the individual existence 

 can be but too readily recognised, the real end of life, so far 

 as the whole race of living creatures whether plant or 

 animal is concerned, is as incapable of being appreciated 

 by the physiologist as is its beginning. 



