Mr BAXTER, ON ORGANIC POLARITY. 259 



be no reason why it should not be so considered in regard to organic action, viz. during 

 secretion ; but before we arrive at this conclusion let us compare the phenomena of secretion 

 with another class of facts, viz. with those of osmose. 



Professor Geaham has communicated a very valuable paper to the Royal Society, entitled 

 On Osmotic Force, which has lately appeared in their Transactions*. In this paper 

 Professor Graham has shewn that osmose is dependent upon chemical action, and not as it 

 has been generally supposed, upon capillary attraction. Time will not allow me to enter 

 upon the facts brought forward in support of this opinion, and I must therefore refer to the 

 paper itself, which cannot be too strongly recommended. 



The conditions under which an osmotic experiment is conducted, viz. the necessity of 

 having two fluids, one on each side of the septum, render it extremely difficult to ascertain by 

 means of the galvanometer the exact mode of action which arises during osmose, so as to com- 

 pare it with that which takes place in the animal body during secretion, in consequence of 

 the reaction of the two fluids upon each other producing their own peculiar effects on the 

 galvanometer ; and the changes upon which osmose depends take place, according to Professor 

 Graham, within the substance of the porous diaphragm, where we cannot apply the elec- 

 trodes of the galvanometer. 



The fact of osmose depending upon chemical action shews however that the act itself must 

 not be considered as a mere transudation, a mere physical separation, but that it depends 

 upon other important conditions ; and if upon chemical action they are consequently polar in 

 their nature. If this conclusion be arrived at in regard to osmotic phenomena we may with 

 equal propriety consider the phenomena connected with secretion to be at least something more 

 than a mere physical transudation ; and as reasons exist for shewing that osmotic phenomena 

 are polar in their nature, why may we not consider the action connected with secretion, and 

 where we can obtain such direct evidence of polar action, as manifested by the galvanometer, 

 to be polar in their nature also.? 



Eespecting the chemical character of osmose, and its bearings upon physiology, Professor 

 Graham adds : — " It may appear to some that the chemical character which has been 

 assigned to osmose takes away from the physiological interest of the subject in so far as the 

 decomposition of the membrane may appear to be incompatible with vital conditions, and 

 osmotic movement confined therefore to dead matter. But such apprehensions are, it is 

 believed, groundless, or at all events premature. All parts of living structures are allowed to 

 be in a state of incessant change — of decomposition and renewal. The decomposition occur- 

 ring in a living membrane, while efi^ecting osmotic propulsion may possibly be of a reparable 

 kind. In other respects chemical osmose appears to be an agency particularly well adapted 

 to take part in the animal economy." 



The subject of the present communication has been that of Organic Polarity, and to 

 this it has been my endeavour to confine our attention, and to shew that some of the organic 

 actions which occur in the animal body, viz. secretions, are evidently accompanied with the mani- 

 festation of current force ; a fact which may not be disputed. An endeavour has been made 



• Phil. Trans. 1864. 



33—2 



