36 PROTOPLASMIC THEORY BEFORE 1860. 



position but consisted essentially of protoplasm and cell fluid. 

 He admits, in the cortical layer of the protoplasm, a distinct 

 arrangement into layers often occurs, but these cannot be differ- 

 entiated as a membrane primordial utricle and subjacent 

 protoplasm. He states that he has coloured blue the outer- 

 most layer of protoplasm in confervce, so most probably, he 

 thinks, the primordial utricle is really the most recently formed 

 layer of the permanent cell-wall. In fact, from what appears 

 in the foregoing and what is now generally held, the primordial 

 utricle seems to be merely the outer layer of this protoplasm 

 and not a distinct part. Still Henfrey thinks it better to re- 

 tain the name to express the formative stratum of living proto- 

 plasm. "In animal cells," according to Pringsheim, "partly 

 from their small size and partly from their greater wealth of 

 protoplasm, it is rarely possible to make a sharp demarcation 

 between a cortical layer of protoplasm and a cell-fluid ; never- 

 theless there exists a difference in the constitution of the 

 former, such that a cutaneous layer destitute of, or scantily 

 furnished with, granules encloses the remaining more granular 

 material. The white blood cell may serve as an. example. This 

 however is very different from a proper membrane " (Qu. Mic. J., 

 p. 252. 1863). 



With respect to the nucleus, we have seen that according to 

 Naegeli, it is wanting in several fungi and lichens, and to Alex. 

 Braun in the Hydrodictyon, Vaucheria, Caulerpa, &c. Also in 

 various forms of amoebae. 



In 1853, Professor Huxley wrote a review * of the then exist- 

 ing literature of the cell theory, which is not only valuable his- 

 torically, but important as an original contribution to it. The 

 following are the most important points. 



That the primordial utricle is the essential part of the endo- 

 plast [i.e., all that is contained within the cell wall], while the 

 protoplasm and nucleus are simply its subordinate, and, it 

 might almost be said, accidental modifications. 



That the process in cell-division, and the histological struc- 

 ture of plants and animals is essentially identical, and thus, for 

 example, the chondrin wall of cartilage is the homologue of the 

 * Med. Cliir. Keview. 



