INTRODUCTION 7 



Science, as known now, has been developed slowly from 

 chaotic notions and first principles, as the empirical gave 

 way before the advancing tide of observation, experiment, 

 and induction, until it has ceased to be a systematic body 

 of knowledge and has become divided and subdivided into 

 a congeries of sciences, more or less separate from each 

 other, and working continuously along more or less rigidly 

 special lines, until the principle of continuity is in danger 

 of being forgotten, and the advantage of concerted move- 

 ment lost, and the great need of simplicity in the handling 

 of large masses of knowledge sacrificed to the requirements 

 of increasing and strengthening specialisation. 



To meet the requirements thus arising it would seem 

 reasonable that some central means should exist that would 

 at once be in touch with the latest advancements in special 

 science and actuated with a keen desire to bring the whole 

 into conformity for general purposes, whether theoretical 

 or practical. 



Thus, principles become deducible from a general sur- 

 vey which would remain undiscovered amid the masses 

 of special knowledge. 



Thus, for example, Harvey, from the mass of pre- 

 existent archaic anatomical knowledge, with his own 

 indefatigable observation and experiment, deduced the 

 principle of the circulation of the blood, and gave to 

 science biological an impetus which is felt at the present 

 day and will continue a force and incentive to men of 

 science throughout all time. 



On the completion of his discovery, and the arrival of 

 the time at which it could be presented to his contem- 

 poraries with a good hope of its acceptance, he found that 

 there was one link which his limited powers of observation 

 could not supply, but which he, with an inductive acumen 

 and a scientific effort of imagination perhaps not surpassed 

 in the annals of research, felt must be a definite structural 

 provision, which, when the microscope arrived, was proved 

 just as he surmised. 



This missing link in the otherwise complete chain of 

 blood circulation was the capillary vasculature, which 

 united the arterioles to the venules, gave the finishing 

 touch to his great work of discovery, and placed the 



