THE CELL DOCTRINE. 127 



of the intracellular with those of the intranuclear network, 

 and along with Eberth, Marchi, and Eimer, traces in 

 the epithelial cells of the foregut of the newt, the 

 cilia in direct continuation through the cell-cover with 

 the fibrils of the intracellular network. 



The intracellular network is less conspicuous than 

 the intranuclear, but possesses the same general 

 characters. 



The importance of this subject has seemed so great 

 that I have added at the end of the volume the essen- 

 tial portions of* the plate from the Quart. Jour, of 

 Micros. Sci., for July, 1878, which, with its descrip- 

 tion, will give a very accurate notion of these new 

 views as confirmed by Dr. Klein, than whom, of 

 modern observers, I consider none more reliable. 



summary — present state of the cell doctrine — 

 author's views. 



Minute analysis of the solids of the organism has 

 long been an object of the histologist and physiolo- 

 gist, which, resulting first in the partes similares of 

 Aristotle and Galen, has finally reached the so-called 

 " cell " or " elementary part " as the ultimate physi- 

 cal element of organization, out of which all tissues, 

 healthy or diseased, are formed. Our ideas as to the 

 exact physical constitution of this elementary part 

 have undergone considerable change since the first 

 announcement by Schleiden and Schwann, in 1838, of 

 its exact physiological position. The most impor- 

 tant modifications of the original conception of a cell 

 is that which removes altogether its vesicular char- 



