ENDOPLAST AND PERI PL AST. 13 



moving substance which it once was ? If this be so, there 

 ought to be no recognizable difference between matter 

 which is actually alive and the substances which result from 

 its death. 



So far, then, we have seen that the term protoplasm has 

 been applied to the matter within the primordial utricle of 

 the vegetable cell, to that clear substance which undergoes 

 vacuolation and fibrillation, and to the matter forming the 

 walls of the vacuoles and the threads or fibrillae. Still more 

 recently, Von Mohl's primordial utricle has been called proto- 

 plasm by Professor Huxley, who some years before restricted 

 the term to the matter within the primordial utricle, which 

 matter at that time he regarded as an "accidental anatomi- 

 cal modification" of the endoplast, and of little importance.* 

 The nucleus, and with it the protoplasm, Mr. Huxley 

 thought, exerted no peculiar office, and possessed no meta- 

 bolic power. Now, however, he considers " protoplasm" of 

 the first importance; and under this term includes, I 

 imagine, not only the primordial utricle and the " accidental 

 anatomical modifications " it encloses, but the fully-formed 

 cellulose wall of the vegetable cell. His "endoplast" and 

 "periplastic substance" of 1853 together constitute his 

 "protoplasm" of 1869. The old views are modified, and 

 although the results of researches made during the last few 

 years are scarcely alluded to, the writer evidently has felt 

 that certain changes must be made. So the vacuoles of his 

 periplastic substance become silently tenanted by simple or 

 nucleated protoplasms endowed with " subtle influences" 

 which our author may yet admit to have existed before his 

 * "The Cell Theory," " Med. Chir. Rev.," October, 1853. 



