Comparative Physiology^. 213 



augment as tlie mass increases, in the same way as galvanism 

 augments by the size of the plates of the battery. We may 

 conceive of life, as a principle similar to electricity, which per- 

 vades all organised matter, as electricity does the inorganic ; 

 and communicates vital properties to the organism, as the other 

 does magnetism to metals. We may pursue the analogy farther, 

 and say that as metals will not retain the magnetic properties, 

 unless in a certain condition, so neither will the m^flter of an 

 organism retain vital properties unless in a certain condition or 

 form ; and as organised living bodies can communicate their 

 vital properties to others, so will magnetic bodies develope elec- 

 tricity. Vitality may thus be a principle so intimately united 

 with vital properties that it is hai'dly possible to distinguish 

 them. There is perhaps as much danger to be apprehended in 

 assuming state or form producing vitality, as in vitality pro- 

 ducing form ; there appears as yet as much logic in the latter 

 supposition as the former. In guarding against mystery we 

 may approach materialism ; and though nothing would appear 

 to be farther from the opinions of the author than this, yet such 

 opinions, argued in a different manner, and carried to extremes, 

 might tend thereto. 



The peculiar influence of sulphuric acid in changing gum and 

 starch into sugar, without being itself changed, is very striking ; 

 it is the same with the conversion of these substances into fibrin 

 by the action of nitric acid and chlorine. They appear a class 

 of actions which approach those of vitality, in so far as that they 

 act on other substances without appearing to be acted on them- 

 selves. The researches of chemists have of late been more 

 directed to organised substances than formerly, and the advance 

 is likely to be correspondingly rapid. As new truths come to 

 be discovered, they are found to connect the former, to clear up 

 confusion, and establish simplicity. Many new bases have been 

 discovered, and it is said by Professor Thomson, in his Vegetable 

 Chemistry, that we may hope soon to have all bodies reduced to 

 a simple and lucid arrangement of alkalies (or alkaloids) and acids, 

 bases and the bodies which they neutralise. Chemistiy has done 

 much to advance physiological knowledge, and more may be ex- 

 pected ; the strides in advance in all sciences are so rapid that it 

 is impossible to set limits to expectation, and vital and chemical 

 aflinities may be found more closely united than at present is sus- 

 pected : but we may err in anticipating too much as Avell as too 

 little ; it is part of our nature to err in extremes. Professor Thom- 

 son says, organic principles are made by the processes connected 

 with vegetable and animal life. They constitute the results pro- 

 ceeding from the chemical skill of the Creator, which is infinitely 

 greater than ours can pretend to be. The immense mass of in- 

 formation contained in the tables of atomic elements, collected 



