THE LAWS OF PROTOPLASM 1 29 



dicate that civilized man has come to regard 

 disease as having a very direct and important re- 

 lation to life. 



"But," we are frequently asked, "do the rest of 

 living beings become sick and die before they reach 

 old age?" The facts bearing upon this subject 

 are not as well known as those just stated in regard 

 to man. The expert upon animals in the Depart- 

 ment of Agriculture estimates that the annual loss 

 from disease in cattle, sheep and hogs is $212,- 

 000,000. A second expert in economic entomol- 

 ogy in the same department estimates the annual 

 loss, by insects alone, to the timber in the forests 

 of the United States as $62,500,000. During 

 the past ten years the Gypsy moth has spread over 

 the New England states and has left them almost 

 treeless in some places. Just now the white-pine 

 blister rust is beginning to destroy the pines in 

 several of the eastern states. We dare not pre- 

 dict how serious this disease may become. The 

 potato blight, the damage done to the cereal 

 plants, the injury to fruits, each tells the same 

 story. 



All the plants and animals just enumerated are 

 of industrial importance but some one may also 

 ask if the unimportant plants and animals are 

 never sick. It does not make any difference where 

 one looks in nature, there he can find organisms 



