164 
REVIEW. 
enough, but which as an imaginary hobby-horse is a most unsafe in¬ 
strument of progression, that we have to fear ; for it may be, when 
duly regarded, a useful stimulus of well-directed work; but it is that 
other principle and system with which it is so often confounded, and in 
exclusive satisfaction, with which it so often ends, namely, the entry 
upon the study of life through the material side alone, and the resting 
contented with such explanations of vital phenomena and processes as 
extend only to a definite and accurate statement of the physical and 
chemical elements which enter into them as component parts.” 
The author does not intend bv these remarks to underrate 
•/ 
the importance of accurate physical and chemical examina¬ 
tion, for wherever physics and chemistry can explain even a 
part of a vital process, they should be used for that purpose, 
and used to the full; and this he illustrates by a reference to 
The Function of Digestion. 
“ In regarding the process of digestion, nothing is to be gained by 
the imagination of some imperial ‘Archaeus,’ seated upon his gastric 
throne, and wielding - the sceptre of royal digestive state; neither is any¬ 
thing gained by supposing a mysterious ‘vital entity,’ or still more an 
imaginable ‘vital intelligence/ or ‘vital force,’ degrading itself from its 
high position to do the low-caste work of a chemical underling; for 
now w r e know that the process is one, the immediate changes of which 
depend simply upon the exercise of ordinary physical and chemical 
agencies ; and, moreover, that the said agencies are (unlike many func¬ 
tionaries) quite equal to their work, and can accomplish it, outside the 
body, and without any vital drilling, interference, or overlooking. But 
when we have separated ‘pepsine/ and even converted it into an article 
of diet, thus bringing up a valuable ‘contingent’ to the support of an 
exhausted stomachwhen we have determined its atomic weight, and 
bestowed upon it the due measure of its titles, that real ‘ reward of 
merit/ its C. II. N. O.;—when we have analysed its compounds, and 
become thoroughly acquainted with the forms and limits of action of 
its most valuable ‘ adjutant/the gastric acid;—when we know all the 
‘ peptones/ and can say how pepsine may, with an alkali for its assist¬ 
ance, change its colours, and come down, as by a flank movement upon 
the unsuspecting- amylaceous compounds :—when we have accomplished 
all this, and much more beside, and have numbered the hours that the 
‘engagement’ between gastric forces and various viands must occupy; 
—when we have definitely weighed the compounds, enumerated the 
‘casualties/ and estimated the waste products that rise in air, is there 
nothing left for us to study; is there nothing that has escaped us; 
nothing that we have left unweighed; nothing that we have failed in 
reducing to our formulae? Is the physiology of digestion summed up 
in this expression of chemical results ? What is there that determines 
the sense of hunger, of thirst, or of satiety, and how do these influence 
the chemical transposition ? What is the nexus between thought, 
deep anxiety, or other emotional disturbances, and those sensations ; 
and through them, or not through them, upon this easily described 
action of the pepsine and its assistant acid? Where do mind and feel¬ 
ing come in contact with these material processes; and how do they 
