AND ITS RELATION TO ANIMAL LIFE 1 59 



among many others I may name the hop fly, 

 turnip fly, oak moth and codlin moth as worthy 

 of special study on these lines. 



What I wish to put forward as my conten- 

 tion is that side by side with the normal vegeta- 

 tion having a proper chlorophyll, there exists 

 a class of vegetable and animal life which 

 depends upon the chlorotic specimens for its 

 food and for its very existence. 



The leading feature of the first form of life 

 is that the plants contain a chemical com- 

 pound known as chlorophyll and the animals 

 a chemical compound known as haemoglobin, 

 which is simply a change of colour produced 

 in the animals when they eat the green colour- 

 ing matter, or the substance which represents 

 it in foods, such as roots, which are not 

 exposed to the sun's rays. 



The second form of life is composed of vari- 

 ous plants and insects, the leading feature of 

 this class being that none of the plants contain 

 any chlorophyll and the insects are devoid of 

 chlorophyll or its red modification haemo- 

 globin. Between these two extremes we have 

 both plants and insects, like charlock and the 

 aphides, as a sort of connecting link. 



