.MIM..IU xxvn. i TIII: EFFECTS OF ALLOTKOHSM. 377 



Berzelius, following the suggestion of Frankenheim, 

 proposes a nomenclature for pointing out the peculiar 

 form referred to in any special case. It depends on the 

 use of Greek letters. Thus, we have the three forms 

 of carbon just alluded to designated on these principles 

 by Co, Cj3, Cy. But in a Memoir republished in this 

 work, p. 285, it is remarked that we may often with 

 greater convenience use the simple expressions "active" 

 and "passive." Thus, active chlorine is that which will 

 decompose water in the dark, passive chlorine failing to 

 do so. In this Memoir the same expressions will be em- 

 ployed. 



Hitherto, allotropism has only been considered as af- 

 fecting inorganic states of matter, but its influence can 

 be plainly traced in the far more interesting case of or- 

 ganic beings ; and this, when placed in a proper point 

 of view, yields a remarkable explanation of some of the 

 most obscure but important facts in physiology and 

 pathology. These explanations I propose now to point 

 out. 



In the Philosophical Magazine (March, 1846, p. 178) 

 there is a paper by me explanatory of the causes of the 

 circulation of the blood in the capillary vessels. It is 

 merely an abridgment of a lecture which for eight years 

 past has been delivered in this university. The doctrine 

 there set forth has been generally received in America, 

 and introduced into some of the standard works on 

 physiology published in England. The principle on 

 which it essentially depends, and which has been abun- 

 dantly confirmed by direct experiment, is briefly this 

 that if there be tw r o fluids occupying a capillary tube, or 

 a porous structure of any kind, under the condition that 

 one of them has a stronger chemical affinity for the sub- 

 stance of that tube or structure than the other, a move- 

 ment of the liquids will at once ensue, that which has 



