PLASM 



which a body can be divided without altering its chemical 

 character. Hence the molecules of every chemical com- 

 pound are made up of two or more atoms of different 

 kinds. The greater the number of atoms in each com- 

 pound, the higher is its molecular weight. The space 

 between the molecules and their component atoms is 

 filled with imponderable and highly elastic ether. As 

 even the largest molecules occupy only a very tiny 

 space, and remain far below the range of the most power- 

 ful microscope, all our ideas of their composition depend 

 on general physical theories and special chemical hy- 

 potheses. Nevertheless, stereochemistry, the modem 

 science of the molecular structure of chemical com- 

 pounds, is not only a perfectly legitimate section of nat- 

 ural philosophy, but it yields the most important con- 

 clusions as to the mutual attractions of the elements 

 and the invisible movements of the atoms in combining. 

 It further enables us to calculate approximately the 

 relative size of the molecules and the number of atoms 

 that are grouped together in them. However, the 

 albuminoids present the greatest difficulty of all in this 

 calculation, and their structural features are still very 

 obscure. Nevertheless, science has reached certain 

 general conclusions, which we may formulate in the 

 following propositions : 



1. The molecule of albumin is unusually large, and 

 therefore its molecular weight is very high (higher than 

 in thost or all other compounds). 



2. The number of atoms composing it is very large 

 (probably much more than a thousand). 



3. The disposition of the atoms and groups of atoms 

 in the albuminous molecule is very complicated, and at 

 the same time very u^istable — that is to say, very 

 changeable and easily altered. 



These characters, which are ascribed to all albuminous 

 bodies by modern chemistry, hold good of all plasma- 



127 



