PLASM 



plasm. All the other materials that we find in the 

 living organism are pro4ucts or derivatives of the active 

 plagm. 



In view of the extraordinary significance which we 

 must assign to the plasm^ — as the universal vehicle of all 

 the vital phenomena (or "the physical basis of life," as 

 Huxley said) — it is very important to understand clearly 

 all its properties, especially the chemical ones. This 

 is rendered somewhat difficult from the circumstance 

 that the plasm is, in most of the organic cells, closely 

 bound up with other substances — the various plasma 

 products; it can rarely be isolated in its purity, and can 

 never be had pure in any quantity. Hence we are for 

 the most part dependent on the imperfect, and often 

 ambiguous, results of microscopic and microchemical 

 research. 



In every case where we have with great difficulty 

 succeeded in examining the plasm as far as possible and 

 separating it from the plasma-products, it has the ap- 

 pearance of a colorless, viscous substance, the chief 

 physical property of which is its peculiar thickness and 

 consistency. The physicist distinguishes three condi- 

 tions of inorganic matter-^soHd, fluid, and gaseous. 

 Active living protoplasm cannot strictly be described as 

 either fluid or solid in the physical sense. It presents 

 an intermediate stage between *the two which is best 

 described as viscous ; it is best compared to a cold jelly 

 or solution of glue. Just as we find the latter substance 

 in all stages between the solid and the fjuid, so we find 

 in the case of protoplasm. The cause of this softness is 

 the quantity of water contained i|i the living matter, 

 which generally amounts to a half of its vorume and 

 weight. The water is distributed between the plasma 

 molecules, or the ultimate particles of living matter, in 

 much the same way as it is in the crystals of salts, but 

 with the important difference that it is very variable in 



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