370 Thoughts on Species. 



outset, the endless diversities in individuals, and suggesting 

 numberless questions that vary in answer for eacli kingdom, 

 class or subordinate group. It is better to approach the subject 

 from a profounder point of view, search for the true idea of dis- 

 tinction among species, and then proceed onward to a considera- 

 tion of the systems of variables. 



Let us look first to inorganic nature. From the study of the 

 inorganic world, we learn that each element is represented by a 

 specific amount or law of force ; and we even set down in num- 

 bers the precise value of this force as regards one of the deepest 

 of its qualities, chemical attraction. Taking the lightest element 

 as a unit to measure others by, as to their weights in combination, 

 oxygen stands in our books as 8 ; and it is precisely of this nu- 

 merical value in its compounds : each molecule is an 8 in its. 

 chemical force or law, or some simple multiple of it. In the 

 same way there is a specific number at the basis of other quali- 

 ties. Whenever then the oxygen amount and kind of force was 

 concentered in a molecule, in the act of creation, the species 

 oxygen commenced to exist. And the making of many such 

 molecules instead of one, was only a repetition in each molecule, 

 of the idea of oxygen. 



In combination of the elements, as of oxygen and hydrogen, 

 the resultant molecule is still equivalent to a fixed amount, 

 condition, or law, of chemical force ; and this law, which we ex- 

 press in numbers, is at the basis of our notion of the new species. 



It is not necessarily a different amount of force ; for it may 

 be simply a diff"erent state of concentration or different rate or 

 law of action. This should be kept in mind in connection with 

 what follows.* 



The essential idea of a species, thence deduced is this : a spe- 

 cies corresponds to a specific amount or condition of concentered 

 force^ defined in the act or law of creation. 



* When we have in view, oxygen and the elements, we are apt to 

 think of their molecules as distinguished by a different amount and kind 

 of force. But when we consider the manydifferent compounds that may 

 be made of the same elements (as carbon and hydrogen), in the very 

 same proportions, we are led to conceive of these as differing molecu- 

 larly in a different law of the same force or forces. When, again, we 

 see the same element under conditions as diverse as any two compounds, 

 as in cases of allotropism, we are still better satisfied with adopting, for 

 the present, the most general expression — a different law of action or 

 condition of molecular force. 



