12 



capable of being proved, — that all the different forms of 

 animal and vegetable life may have sprung originally from 

 at most but a very few primitive germs, which, by continued 

 development under constantly altering conditions of life 

 through a long succession of ages, have given rise to all the 

 different species and varieties we see at the present day, 

 whether in the fossil or living state. Into these speculations 

 we will not enter. I only mention them in connection with 

 what I previously stated, — to show how necessary it is for the 

 student of any particular department of Natural History to 

 be acquainted in a general way with all the other departments. 

 Whether the several species of animals and plants have had 

 an independent origin or not, they shew mutual affinities often 

 of the closest kind. It is quite impossible to string them 

 all together in one straight line reaching from the lowest to the 

 highest as was formei'ly supposed: they rather form a compli- 

 cated network, radiating and branching out in all directions, 

 each species showing relationships more or less striking to a 

 multitude of others. They are all subject to the same general 

 laws of organization ; and there are certain first principles of 

 life and structure, as well as of classification, which apply to 

 all alike, and which must be understood by him who desires 

 to investigate their natural history with any hope of success. 



A general knowledge of science in all its branches is 

 advantageous to the student in another way. It is calculated 

 to remove that narrow-mindedness which sometimes attaches 

 to those who confine themselves to one department of it 

 exclusively. The physicist has occasionally looked down upon 

 the naturalist as devoting his attention to objects of inferior 

 consideration to those which he himself studies. Even among 

 naturalists, those who have chosen for themselves the study of 

 the higher animals have sometimes underrated the labours 

 of the conchologist and entomologist, and yet more the 

 researches of others, who, perhaps, give all their time and 

 attention to the investigation of the minute infusoria, or of 

 those most repulsive of all animated forms — the entozoa. 



It may be true that, at the present day, feelings such as 

 these are not entertained so much as formerly, and that men 

 of whatever rank who devote themselves to science at all, are 

 considered but as fellow- workers in a common field. But 

 still there is a narrow-mindedness, which, without any reference 

 to others, may hinder us in our own studies, when too confined, 

 in respect of the method in which we conduct them and the 

 judgments we form. Naturalists, especially, who are only 

 acquainted with one particular class of animals, have been fre- 

 quently led to entertain erroneous estimates of the importance of 

 certain organs and characters, from taking a too limited view 



