NUCLEUS AFTER 1860. 103 



constituents as it, and is, when present, an important 

 part of the protoplasm" ("Physiologic," p. 8). Van 

 Beneden, in his recent memoir on the Gregarinse (" Qu. 

 Mic. J.," 1871), gives some general remarks on the cell 

 theory, from which we may extract the following : 

 " The existence of the monera, which have been the 

 origin of all living beings, and whose simplicity is 

 found again in the youngest Gregarinse, proves the 

 existence of the plasson [Protoplasm] (see note, p. 45), 

 as the primitive condition. But in the plasson the 

 nucleolus appears before the nuclear layer. If we 

 identify plasson with the blastema, such as Schwann 

 understood it, we shall return to the views of the cele- 

 brated histologist who assigned to the cell a centri- 

 fugal evolution." This is in accordance with what I 

 have said at pp. 25, 27, and if we look upon the 

 nucleolus and nucleus in the light of organs, in the 

 lower independent individuals, as stated at p. 58, we 

 shall escape the difficulties of this question. In one 

 of the most recent notices of cell theories, viz,, that by 

 Professor Cleland,* substantially the same opinions are 

 expressed, although the author raises a useless ques- 

 tion whether certain non-nucleated organisms should 

 not rather be regarded as cell nucleus, instead of proto- 

 plasm. From all this it is evident that general opinion 

 is now in accord as respects the facts with Dr. Beale's 

 statements on the nucleus in 1860, and I think his 

 theoretical views of it (see p. 60) will appear to most 

 to be in harmony with these facts. As regards the cell 

 .theory as a whole, also little difficulty will be felt in 



* "Qu. Microsc. J.," July, 1873. 



