148 THE AMERICAN MONTHLY [Aii2:nst, 



nucleus and the latter in the rest of the cell. But this is only a beginning ; 

 for these bodies have been still further resolved, and one investigator in this 

 line finds not less than five different chemical compounds in the nucleus alone, 

 and still others in the cytoplasm outside of the nucleus. Chemical differences, 

 too, between the protoplasm when living and when dead have been detected ; 

 the former having the power to decompose certain of the nobler metals from 

 their solutions, while the latter has not this power. Numerous points of like- 

 ness have been traced between the activities of protoplasm and ordinary chem- 

 ical processes. Urea, formic acid, oxalic acid, salacilic acid, alcohols, ethers, 

 glycerine, wintergreen, vanilla, cinnamon, camphor, etc., all substances for- 

 merly thought to be possible of production by the means of protoplasm alone, 

 have now been manufactured by purely synthetic processes in the chemist's 

 laboratory. Oxidizing and reducing processes are constantly going on, and to 

 these many of the activities of protoplasm may be referred. It is stated that 

 when lifeless protoplasni becomes living, heat is rendered latent. Motion of 

 protoplasm is said to be due to the stretching and contracting of the proto- 

 plasmic fibres caused by changes in its density, the result of oxidizing and re- 

 ducing changes. Much of this is, of course, crude hypothesis, and, as yet, 

 largely guess-work ; particularly is this true as to the relation of the activities 

 of protoplasm and chemical changes. The subject is, as yet, only in its in- 

 fancy, but we are certainly beginning to know something about the chemistry 

 of protoplasm. We know that it is not a definite chemical compound, and 

 that protoplasm itself can no longer be called the physical basis of life. If 

 we are to speak of a physical basis it must be of the microsomata ; and really 

 we have no reason to think that these are the ultimate life elements. 



Naturally the content of our conception of the organic cell has been greatly 

 changed by this study. It was formerly called the unit of organic life. It is 

 now known to be a complex colony of such units, if indeed such units can any 

 longer be said to exist. At first the cell was regarded as a cell in the true 

 meaning of the woi'd, and the cell wall was looked upon as an essential part 

 of it. The cell wall was soon found to be only a secretion from the proto- 

 plasm, and this was, therefore, then regarded as the essential part. But this 

 left the nucleus without any meaning. The importance of the nucleus slowly 

 grew in the minds of cytologists. It was found to be almost universally present 

 in cells, and, to-day, cytologists think that it is really always present, though 

 sometimes in a diffused state, which renders it not readily visible. It was 

 found that the nucleus always began cell division and had an important part 

 to play in fertilization and reproduction in general. When the more minute 

 anatomy of the cell was further studied the importance of the nucleus was 

 still more apparent. It is in the nucleus that all initiative processes of cell 

 life begin. When the union of sexual elements takes place it is really the 

 nuclei that unite. For the spermatozoan is really a part of the mother cell 

 in the testis, and this unites with the germinal vesicle of the egg which is i/s 

 nucleus. Of course it follows from this that the nucleus is the sole organ 

 for the transmission of inherited characteristics, and it must contain the es- 

 sential life essence, whatever that may be. It is found that life may go on in 

 a fashion without a nucleus being present in the protoplasm. Experimenters 

 have artificially divided the cells of large protozoa and found that each piece 

 would continue its life processes ; but only those containing a bit of the 

 original nucleus were able to reproduce themselves by fission or otherwise. 

 Thus it is shown that without the materia) which is present in the nucleus 

 there is no possibility of perpetuation of species. In accordance with its im- 

 portant functions, the nucleus is found to be correspondingly complicated, 

 not only in its chemical nature, but also in its structure. The protoplasmic 

 reticulum is here the most dense, the microsomata are the most abundant. 



