IMPORTANCE OF CAPILLARY ATTRACTION IN PHYSIOLOGY. 35 



rious and incomprehensible. This unphilosophical impression exists not only in the 

 minds of the vulgar, but has extended itself to men well trained to scientific research ; 

 it is to be found in the writings of the most eminent physicians, and often affords a 

 plausible screen for professional ignorance. Of all the sciences, medicine is the last to 

 profit by the analytic method a method which has raised other departments of knowl- 

 edge to their present rank. Its cultivators pursue the same course of synthesis which 

 was pursued in the days of the Greeks they reason from hypothesis to fact, instead 

 of from fact to hypothesis. 



107. It may, however, be boldly declared, that the science of life is not more occult 

 than any other of the sciences. We may, by proper investigation, carry it as far ; and 

 we shall only stop short at the very same point which has proved impassable in them. 

 Of final causes we know nothing; the immediate agent of life is not more obscure 

 than any of the remote physical agents. If we cannot assign any reason why a seed 

 germinates, can we tell why a stone falls to the earth 1 is the one phenomenon any more 

 comprehensible than the other ? If we cannot tell how it is that one parent should 

 produce a countless offspring, each of which has the power of reproducing beings like 

 itself, neither can we tell how a spark produces an extensive conflagration. It avails 

 us little to say that the principle of life, like the principle of heat, possesses a radiant 

 character, or has a power of self-production. We are equally ignorant how the wide- 

 spreading flame results from a spark, and how countless myriads of seeds have origina- 

 ted from one primordial germ. 



108. Some parts of the science of physiology are doubtless within the reach of scien- 

 tific investigation. Most of the functions of organic life are of this character. Absorp- 

 tion, secretion, circulation, and respiration are carried on through the medium of tubu- 

 lar arrangements of different kinds, endued with specific powers. We are not well in- 

 formed of the nature of these actions, nor of the force giving rise to them. The changes 

 taking place in organic structures partake partly of a mechanical, partly of a chemical 

 aspect, bearing some similarity to other physical changes effected by known agents, yet 

 not identical with them. Some have supposed that the attraction of affinity, or the force 

 of capillarity, was the power in question, operating in an unusual manner, under unusual 

 circumstances ; but the majority of medical writers have cut the knot, instead of untying 

 it, and assert that it is a peculiar force, recognised under the title of vital force, life, or 

 nature. 



109. It is, however, most unphilosophical to resort to these vain explanations, which, 

 after all, afford us no information, substituting only obscure terms as the causes of events 

 not more obscure. Had we approached the problem of pore-action in the same spirit 

 that has led to the development of the causes of magnetic action, a similar and equally 

 striking advance would have been made. 



110. Capillary attraction, considered simply as a mechanical force, is not competent 

 to produce those changes which the pores and narrow cylinders of organic structures 

 give rise to. The products of glandular action are chiefly compounds of a definite 

 number of equivalents, bearing a strong resemblance to the products of ordinary chem- 

 ical action; but still the operation of capillarity as a force producing motion is undeni- 



