42 COMPENDIUM OF GENERAL BOTANY. 



only a property of the innermost part of the middle lamella, which 

 part DIPPEL designated as the middle plate or intercellular sub- 

 stance. This middle plate of the middle lamella is common to two 

 contiguous cells ; on either side of it lies the outer layer of the 

 middle lamella, each one belonging to one of the cells. The outer 

 layer of the middle lamella is soluble in concentrated H 2 S(X , while 

 the middle lamella is not. 



Finally we will mention that, similarly to the middle lamella 

 of the outermost surface of the cell-wall, the surface turned toward 

 the primordial utricle is also lined with a highly refractive thin 

 membrane, the inner membrane of WIESNER, which according to 

 this author is rich in albuminoid substances. 



It has been discovered recently that some intercellular spaces 

 are lined with plasmic substances. Whether the occurrence of this 

 plasmic substance is general or not we must for the time leave 

 undecided. 



Y. THE OKIGIJST OF CELLS. 



Science knows no other method for the origination of cells than 

 the development of new cells from pre-existing ones. The first 

 plants which existed on the earth, hence also the first plant-cells, owe 

 their origin to a command of the Creator issued to lifeless matter : 

 " Let the earth bring forth. . . ." The Bible and science complete 

 each other. The latter answers by investigation the question as to 

 the method of the origin of new cells from pre-existing ones. It 

 can give no natural method for the origin of the first plant-cells. 1 



There are various ways in which plants may form new cells 

 from pre-existing ones. Because these various ways are sometimes 

 not sharply defined, it is at once evident that to obtain a clear idea 

 of what does take place it is necessary to discuss typical cases. 



We distinguish four types of cell-formation, as follows : 



I. Cell-formation *by rejuvenescence, or direct cell-formation. 

 II. Cell-formation ~by conjugation. 



III. Free cell-formation. 



IY. Cell-formation ~by division (meristematic). 



I, II, and III are essentially concerned in the reproductive 

 processes of plant-life, that is, they serve to propagate the individ- 



1 This introductory paragraph, to say the least, is very unscientific. It does 

 not assist the advance of science. TRANS. 



