232 Transactions of the American Institute. 



material or immaterial sometliing, more or less separable from the 

 material body, and more or less identical with the mind or soul, 

 which is the cause of the plienomena of livinc^ beings. But as sci- 

 ence moved irresistibly onward, and it became evident that the forces 

 of inorganic nature were neither deities nor imponderable fluids, 

 separable from matter, but' were simple affections of it, analogy 

 demanded a like concession in behalf of vital force.* From the 

 notion that the effects of heat were due to an imponderable fluid 

 called caloric, discovery passed to the conviction that heat was but a 

 motion of material particles, and hence inseparable from matter. 

 To a like assumption concerning vitality it was now but a step. 

 The more advanced thinkers in science of to-day, therefore, look 

 upon the life of the living form as inseparable from its substance, 

 'and believe tliat the former is purely piienomenal, and only a mani- 

 festation of the latter. Denying the existence of a special vital force 

 as such, they retain the term only to express the sum of the phe- 

 nomena of living beings. 



In calling your attention this evening to the correlation of the 

 physical and the vital forces, I have a twofold object in view. On 

 the one hand, I would seek to interest you in a comparatively recent 

 discovery of science, and one which is destined to play a most impor- 

 tant part in promoting man's welfare ; and on the Other, I M'ould 

 inquire what part our own country has had in these discoveries. 



In the first place, then, let us consider what the evidences are that 

 vital and physical forces are correlated. Let us inquire how far 

 inorganic and organic forces maybe considered mutually convertible, 

 and hence, in so far, mutually identical. This may best be done bj 

 considering, first, what is to be understood by correlation ; and, 

 second, how far are the physical forces themselves correlated to each 

 other. 



At the outset of our discussion, we are met by an unfortunate 

 ambiguity of language. The word force, as commonly used, has 



affinity, and prevents the elements of bodies from freely uniting, we call vital." But in a note to 

 the allegory above mentioned, added to the third edition of the Views of Nature, in 1849, he says: 

 "lieflociion and prolonged study in the departments of physiology and chemistry have deeply 

 shaken my earlier belief in peculiar so-called vital forces. In the year 17!)7, ♦ ♦ • I already 

 declared that I by no means regarded the existence of these peculiar vital forces as established." 

 And again: "The difHculty of satisfactorily referring the vital phenomena of the organism to 

 physical and chemical laws depends chiefly (and almost in the same manner as the prediction of 

 meteonilogical processes in the atmosphere) on the complicatiiin of the phenomena, and on the 

 great number of the simultaneously acting forces as well as the conditions of their activity." 



* Compare Henry Bencc .Jones' Croouian Lectures on Matter and Force. London, 1868, John 

 Churchill & Sons. 



