122 



NA TURE 



iDc 



1885 



Movements : dependent upon the contractions of muscles 

 and the existence of mechanical contrivances connected 

 therewith. (2) Activity of t lie Nervous System; in con- 

 trolling in various ways and in relation to various external 

 and internal conditions the before named movements. 

 (3) Chemical Changes ; these are briefly sketched as not 

 only those directly con:erned in the contraction of 

 muscle, but as occurring in all parts of the body. They 

 may be regarded as a slow combustion in which complex 

 substances full of latent energy are reduced to simpler 

 stable conditions with less or with no latent energy. 

 Li!<e St. Paul, the animal, says Dr. Foster, "dies daily." 

 " All the inner labour of the body, both that of the 

 chemical gland-cells, of the vibrating nerve-substance 

 with.its accompanying changes of consciousness, and of 

 the beating heart and writhing visceral muscles, is, sooner 

 or later, by friction or otherwise, converted into heat ; 

 and it is as heat that the energy evolved in this labour 

 Jeaves the body." Only as heat or as motion of limbs 

 jaws, &c., does the energy set free in the animal body 

 make itself externally apparent. This combustion and 

 degradation of material necessitates new supplies, and 

 hence we have the phenomenon of the inception of food 

 and the chemical processes connected with it. 



The Problems of Physiology are then stated as the 

 result of the preceding survey of the actions of a living 

 being to be as follows: — (i) To discover the laws of 

 transmutation of complex unstable food into still more 

 complex living flesh, and the laws by which the latter 

 breaks down into waste products, void of energy. (2) 

 To discover the laws of the origin of nervous vibrations, 

 of their passage to and fro in nerve substance and of their 

 ultimate disappearance in connection with muscular con- 

 traction or otherwise. (3) To discover the laws of how 

 the energy of chemical action is transmuted into and 

 serves as the supply of that vital energy which appears as 

 movement, feeling, and thought. 



This rough analysis of the problems of physiology is 

 " the residue of many successive phases of opinion." It 

 is in tracing the influence of these successive phases and 

 estimating the value of their residues that the skill of 

 Prof. Foster is mast successfully exerted. Such an 

 appreciation of the historical significance of the various 

 factors of his science, should, we think, be as much the 

 indispensable possession of a cultivated specialist as is a 

 knowledge of his country's political history to the 

 statesman. 



The exigencies of life. Dr. Foster tells us, early directed 

 man's attention to the phenomena of the animal body 

 and thus brought the study of physiology to the front 

 before its time. Hence in the absence of the knowledge 

 of physics and chemistry, explanations were assigned to 

 those phenomena of animal bodies which were not 

 obviously identical with those of inanimate bodies, under 

 the names "vital spirits" and " animal spirits." In the 

 seventeenth and eighteenth century, however, the pro- 

 gress of anatomical knowledge led to the perception of 

 the fact that the animal body contained, if it did not actu- 

 ally consist of, a number of mechanical contrivances each 

 of which could be shown to perform some service in the 

 animal economy for which its construction especially 

 fitted it. In this way grew up the doctrine of " organs" 

 and " functions," and it was held that the inspection of 



structure was sufficient to enable an acute observer to 

 determine the particular function of any given part. 

 Great progress was made under the influence of this 

 doctrine — the most notable example of its triumph being 

 the discovery by Harvey of the function of the heart and 

 the mechanism of the circulation of the blood. The 

 doctrine of vita! and animal spirits still survived as giving 

 an explanation of the motive force which set the compli- 

 cated machinery of connected organs at work. 



In the physiological "cell-theory" of Schleiden and 

 Schwann the adequacy of the doctrine of organs and 

 functions to explain the phenomena of life, whilst appa- 

 rently finally established, received, according to Dr. 

 Foster, its death-blow. It appears to us that Dr. Foster 

 does not quite give its true significance to "the cell- 

 theory." It is true that the founders of that theory 

 attached undue importance to the structural characters 

 of the cell. But Schwann at any rate attached the 

 greatest importance to the cell-substance, and to its mole- 

 cular and atomic constitution, and the doctrine that 

 function is dependent on structure, when by structure we 

 understand not merely coarse visible structure, but mole- 

 cular structure, which difters in any two cases by a differ- 

 ence of internal movement of molecules rather than by 

 a difference of their permanent position — this doctrine 

 is triumphant to-day, and is proclaimed in that portion 

 of the present article which treats of different kinds of 

 protoplasm. 



A quotation is given from a well-known article by 

 Prof Huxley, written thirty years ago, in which it is 

 stated that cells "are no more the producers of the 

 vital phenomena than the shells scattered in orderly 

 lines along the sea-beach are the instruments by which 

 the gravitative force of the moon acts upon the ocean." 

 ."Vpparently Dr. Foster thinks this statement to be defens- 

 ible even to-day, but the conception of living matter and 

 of the significance of cell-substance and structure thus 

 indicated appears to us to be more difficult to reconcile 

 with the modern doctrine of protoplasm than is the 

 doctrine of Schwann, which, to use his own words, was 

 " le contraire de la th^orie generalement admise pour les 

 animaux, d'apres laquelle une force commune construit 

 I'animal ^ la maniere d'un architecte," and which argued 

 from the uniform construction of organisms by modifica- 

 tion of the nucleated corpuscles called cells that " c'est 

 partout la meme force qui reunit les mol(!cules en cellules, 

 et cette force ce ne pouvait plus ctre que celle des mole- 

 cules ou des atonies ; le phdnom^ne fondamental de la 

 vie devait done avoir sa raison d'etre dans les proprietds 

 des atomes " — that is to say, in the atoms of the substance 

 of which the cells consist which has now received the 

 name protoplasm. 



Dr. Foster next gives a vivid picture of the importance 

 of the discovery by Claud Bernard of the glycogenic 

 function of the liver— a function which could not be 

 inferred from the inspection of the liver either macroscopic 

 or microscopic. Such discoveries as these led to the 

 recognition of the existence of most important processes 

 or " functions " in the animal body which had no corre- 

 lative in visible structure. Thus physiologists were led 

 to see in the mind's eye the invisible structure of cell- 

 substance and the " protoplasm theory " obtained its 

 foundations. 



