TO PHYSIOLOGY AND PATHOLOGY. 21 



wood, and acquires the property of combining, at the ordinary temperature, with 

 the oxygen. 



Under similar circumstances the vapour of alcohol absorbs oxygen, and becomes 

 changed into acetic acid. 



THE FIBRIN OF THE BLOOD AND YEAST ACT SIMILARLY TOWARDS 

 BINOXIDE OF HYDROGEN. 



Fresh fibrin stands in the same relation to air as damp wood, passing equally 

 into a state of decomposition ; if, in this condition, it be decomposed by binoxide 

 of hydrogen, the latter is immediately resolved into oxygen and hydrogen ; but if 

 the fibrin be heated to boiling, this accelerating action ceases entirely. Yeast 

 behaves in a like manner, occasioning an immediate decomposition of the con- 

 stituents of the binoxide of hydrogen ; but if it be previously heated to boiling, 

 the action ceases. (Schlossberger.) 



RELATION OF COMBINED ORGANIC ATOMS AMONGST THEMSELVES. 



These properties are in the highest degree appreciable in complex organic 

 atoms. The larger the number of individual elements and atoms, which have 

 associated themselves into a group of atoms of definite properties, and the more 

 various the directions of their attractions, the smaller in the same relation must the 

 force be which attracts together every two or three of the minutest molecules of 

 the group ; they offer a slight resistance to the causes whether heat or chemical 

 affinities which effect a change in their form and properties ; and are as easily 

 changed and decomposed as other substances of simple combination. 



PUTREFACTION. 



The constituents of plants and animals into which sulphur and oxygen enter are 

 formed of compound organic atoms ; from the moment they are separated from the 

 body, and come in contact with the air, they pass into a state of decomposition, 

 which, once begun, continues even after the air is excluded. The colorless 

 sections of a potato, turnip, or apple, soon become discolored and brown on 

 exposure to the air. 



In all these substances, the presence of a certain quantity of water, by which 

 the minutest parts receive mobility, is a necessary requirement, in order that on a 

 transient contact with the air a change of form and properties, and a breaking up 

 into new products may be called forth ; both of which continue until not a particle 

 of the original body remains. . This process has been familiarly designated by the 

 term putrefaction. 



AFFINITY NOT THE CAUSE OF PUTREFACTION. 



Experience teaches us further, that a number of substances brought in contact 

 with these putrefying sulphurous and oxygenous matters, when in the act of 

 putrefaction, in like manner change their properties ; in the act of decomposing, 

 their elements, group themselves into new products, in the composition of which 

 there are, in most cases, none of the elements of the putrefying substances taken 

 up. From all these phenomena it is clear that the decomposition of the second 

 body is not effected in consequence of an indication of affinity, since the idea of 

 affinity is inseparable from the idea of combination. 



