March 23, 1893] 



NATURE 



489 



of life, ihe obscure expression ^vaa, nattira ; but in vain 

 does one seek for a more exact definition of the term. To 

 Paracelsus nature was living, and the basis of his life was that 

 very "archaeus,"a force differing from matter, and separable 

 from it, or, as he himself expressed it, in the sense of the 

 Arabs, a spirit, "spiritus." In the compound organism of man, 

 the mikrokosmos. each part, according to him, had its own 

 "archseus," but the whole was ruled by the "archaeus maxi- 

 mus," the "spiritus rector." From this premiss has proceeded 

 the long succession of vitalistic schools, which, in ever-changing 

 forms, and with ever new nomenclature, introduced into the 

 notions of physicians this idea of a fundamental principle of life. 



If the sagacious Georg Ernest Stahl, whose services to the 

 development of chemistry are now acknowledged everywhere, 

 substituted the soul for the "spiritus rector," and so created a 

 system of animism, the last vestiges of which have disappeared 

 from the school of Montpellier within our own time only, so also 

 in turn did the pure vitalists build up on the dogma of specific 

 dynamic energies, maintained so stoutly by the physicists, that 

 notion of the vital force, the half spiritualistic and half physical 

 character of which has contributed so much, even in our day, to 

 puzzle and mislead men's minds. 



The doctrine of the vital force found its strongest support in 

 the " Nalur-philosophie," especially in that which, on German 

 ground, soon obtained universal sovereignty. 



This summary exposition of mine has greatly anticipated the 

 historical progress of the evolution of medicine. It is now time 

 to pay proper homage to the great investigator who made the 

 more exact method the ruling one, and at the same time to award 

 to this country, which brought him forth, its important share in 

 determining the new direction of our science. 



Nearly loo years had passed since Vesalius and Paracelsus 

 had begun their work when William Harvey published his 

 " Exercitatio anatomica de motu cordis et sanguinis in 

 animalibus." Here, for the first time, the anatomical examina- 

 tion of living parts was carried through, in an exemplary way, 

 according to experimental methods. All the objections that 

 anatomy concerned itself with dead parts only were thus at once 

 set aside ; living action became the object of immediate obser- 

 vation, and this was done on one of the most important organs, 

 one absolutely necessary to life, the varying activity of which 

 constantly calls for the attention of the practical physician. Not 

 only so, however, but a new mode of observation — the experi- 

 mental method — was thus brought into use for research : a 

 method through which a new branch of medical science, 

 physiology, has been laboriously built up. 



The influence of this one wonderful discovery of Harvey's on 

 the ideas of men of his time, and of his successors, was memor- 

 able. 



Among the men of his time the last support of Galenism dis- 

 appeared with the proof of circulation ; among his successors 

 the comprehension of the causation of local processes dawned 

 for the first time. Very ancient and highly difficult problems, 

 such as inflammation, could now be attacked ; a goodly piece of 

 life also became intelligible, since one of the vital organs them- 

 selves could now be subjected to experiment, and, to the aston- 

 ishment of all, the action of this organ showed itself to be an 

 absolutely mechanical one. The revulsion of thought was so 

 complete that it has become since a difliculty hardly to be over- 

 come to enter even in imagination into the ideas of the older 

 physicians, to whom the circulation of the blood was unknown. 



Nevertheless, in spite of such striking results, the craving of 

 man for more complete understanding remained unsatisfied. One 

 saw the action of the living heart, but how did it live? What 

 was this life, the action of which one saw before one ? In the 

 heart itself the essence of life could not be recognised. 



Harvey turned his attention to another object ; he tried to 

 observe the very beginnings of life in the incubated egg of the 

 fowl and in the embryos of mammalian animals. He thereby 

 soon arrived at the question of the significance of the es^g in 

 general, and enunciated the celebrated dictum, " Omne vivum 

 ex ovo." Owing to the more extensive researches of modern 

 investigators, this dictum, as is m ell known, proved too narrow 

 for the whole animal kingdom, and is no longer exact when 

 applied to plant life. Its validity for the higher animals, on the 

 other hand, cannot be questioned, and it has formed one of the 

 firm standpoints on which researches on sexuality and on the 

 propagation of life have been based. But Harvey, on account 

 of the deficiency of his optical instruments, was unable to see 

 that which he was labouring to discover, namely, the process of 



organisation as such, just as he had been unable in former times 

 to see the continuity of the capillary flow. This imperfection 

 lasted for a long time afterwards ; and thus it happened that even 

 Albrecht von Haller and John Hunter considered the formation 

 of the area vasculosa in the incubated egg of the fowl as the 

 commencement of organisation, and indeed, as the type of 

 organisation itself. 



I will return to this point later on ; but for the present I 

 should like first to draw your attention to a man whose import- 

 ance for the further development of the doctrine of life has 

 always appeared to me to have been uncommonly great and 

 highly significant, but who, nevertheless, has sunk into un- 

 merited oblivion, not only among posterity in general, but 

 also, I think I may be allowed to say, even in the memory of 

 his countrymen. I mean Francis Glisson, who was a contem- 

 porary of Harvey, and whose works appeared almost simul- 

 taneously with those of his more celebrated colleague ; but the 

 brilliancy of Harvey's discoveries was so great that the light 

 which shone from Glisson's work-table almost disappeared. I 

 rejoice that on so auspicious an occasion I may recall the 

 memory of the modest investigator, and may offer him the 

 tribute of gratiture which science hqs to award him. 



When, thirty-five years ago, I published my little essay on 

 "Irritation and Irritability" {Archiv fiir Pathologisclic Ana- 

 tomic itud Fhysiologie, 1858, vol. xiv. p. i), I did not know 

 much more about Glisson than what every student of medicine 

 learns, namely, that there is in the liver a " capsula communis 

 Glissonii," and what was even less known, that this anatomist 

 had written a small work on " Rachitis," which, indeed, was the 

 first of its kind. In my own paper on this disease {ibid. 1853, 

 vol. V. p. 410) I had tried to demonstrate the circumspection 

 and accuracy which are noticeable in this book, and which make 

 it a typical model for all collective investig.itions ; but even at 

 that time 1 overlooked the fact that this was only the smallest 

 merit of this wonderful man. It was only in the further course 

 of my studies on the history of the doctrine of irritation and 

 irritability that I made the discovery, an astonishing one to me, 

 that the idea of irritability did not, as is generally thought, 

 originate with Haller, but that the father of modern physiology, 

 and the Leyden school in which he had been brought up, had 

 borrowed this idea from Glisson. I then stumbled on a series 

 of almost forgotten publications of this original scholar, espe- 

 cially his " Tractatus de natura substantia energeticse seu de 

 vita naturae ejusque tribus primis facultatibus, perceptiva, appe- 

 titiva et motiva," which appeared in London in 1672, and in 

 which the ideas were further worked out, the outlines of which 

 had already been brought forward in his " Anatomia hepatis," 

 published in 1654. In this work (p. 400) the newly-coined 

 word " irritabilitas " appears, so far as I can find 

 out, for the first time in literature. It may be no- 

 ticed, by the way, that the expression "irritatio" is 

 much older. I find it already in Celsus, but with an 

 exclusively pathological signification. It appears, also, occas- 

 ionally in later writers, and to this day it has not, speaking 

 accurately, lo>t this original signification. It is otherwise with 

 Glisson ; to him, irritability is a physiological property, and 

 irritation merely a process of life dependent on the natural fac- 

 ulties of living matter. 



Thus he was led, through a process of "contemplation," to 

 maintain the existence of the " biarchia," the "principium 

 vitse," or the " biusia," the "vita substantialis vel vitae substan- 

 tia." And in order to allow of no misunderstanding as to the 

 scource of his " contemplation," he adds distinctly that this is 

 the "archaeus,"' of Van Helmont— the " vis plastica" of plants 

 and animals. 



In the further course of his philosophical discussions, he never- 

 theless is led into the same by-path, which has misled, even in 

 the most recent times, so many learned men and even excellent 

 observers. This is the by-path of unlimited generalisation. 

 The human mind is only too prone to render intelligible what is 

 unintelligible in particular phenomena, by generalising them. 

 Just as even in recent times an attempt has been made to render 

 consciousness intelligible by representing it merely as a general 

 property of matter ; so Glisson thought he might attribute to the 

 active principle ("principium energeticum") which according to 

 him is contained in all matter the three faculties of living matter 

 which he considered as fundamental, namely, the facultas per- 

 ceptiva, appetitiva et motiva. All matter was sensitive, was^ 

 thus stimulated to develop impulses, and moved itself as a con- 

 sequence of these impulses. 



NO. 



22 1, VOL. 47 



