42 BIOLOGY 



teristics ot their protoplasm. If the characters of mankind are 

 dependent upon the properties of its protoplasm, it follows 

 that the protoplasm that makes up the cells in man must 

 differ as much from the protoplasm that makes up the cells 

 of a plant as mankind differs from the plant. There will be, 

 then, is many varieties of protoplasm as there are varieties of 

 living beings in the world. But apart from these detailed charac- 

 ters, we find that the substance protoplasm, using this term now 

 to refer to the general life substance of the cell, has a few charac- 

 teristics that are present in all forms of protoplasm whether 

 animal or plant. In other words, all forms of living matter 

 possess certain general properties, which are frequently spoken of 

 as the general characters of protoplasm. They are as follows : 

 I. Chemistry of Protoplasm. Various attempts were made 

 in earlier years to determine the chemical composition of pro- 

 toplasm. The chemical elements out of which it is made are 

 easily found to be carbon, hydrogen, oxygen, nitrogen, sulphur, 

 and some other substances in small quantities. For a time it 

 was supposed to be a definite chemical substance with a definite 

 formula, and attempts were even made to give the number of 

 atoms present in a molecule of protoplasm We now know that 

 such attempts were necessarily futile. Protoplasm is not a 

 chemical compound but a mixture of a variety of different com- 

 pounds. The fibrillar network, the liquids, the microsomata, 

 and the chromatin are certainly all different from each other, 

 and it is manifestly impossible to speak of the chemical composi- 

 tion of protoplasm as a whole. We can safely say that proto- 

 plasm contains proteids, but beyond this, little of significance 

 has yet been determined. Since it is in a very unstable condi- 

 tion, constantly undergoing changes, its chemical composition 

 cannot be constant. Moreover, the chemical nature of living 

 protoplasm is doubtless different from the same material when 

 dead, and since any chemical tests are sure to result in its death, 

 it is impossible to determine the composition of the material 

 when alive. 



