242 BOTANICAL GAZETTE. [ October, 



to explain the movements within the cell. It is very difficult 

 to explain in any way the so-called wandering of protoplasm 

 outside the cell wall or into intercellular spaces. 



Fourth, we are to glance at the accepted statement that 

 the protoplasmic body or protoplast, as it is called, of one 

 cell is cut off by the cell wall from all connection with the 

 contiguous cells. There are a few cases in which this inter- 

 vening wall was formerly held to be pervious, but such cases 

 were considered as exceptional. Now, however, as has been 

 shown by Gardiner and others who have followed out his ex- 

 act researches, there are intercommunicating threads of pro- 

 toplasm of extreme fineness between adjoining cells, and 

 these living threads maintain connections, sometimes direct, 

 sometimes indirect, between one protoplasmic mass and an- 

 other. This has been shown to be so widely true in the case 

 of the plants hitherto investigated, that the generalization has 

 been ventured on, that all the protoplasm throughout the plant 

 is continuous. The formation of the dividing wall in cell di- 

 vision is now better understood than ever before, and our 

 knowledge of this process lends great probability to the truth 

 of the general statement made. It is not unlikely, then, that 

 all the living-matter throughout each plant is continuous, a 

 whole, shut off at the time of severing from the mother plant 

 from the body of protoplasm there, and thus making a true 

 chain of descent. 



May I ask you to observe, in passing, how this bears on 

 the vexed subject of individuality of plants. Brucke. in 

 1862, declared that the living protoplasmic contents of a cell 

 formed an elementary organism, and this idea found its full- 

 est expression in the profound work by Hanstein in 1880. 

 In that treatise Hanstein proposed for the living protoplasmic 

 contents of the cell the term protoplast, in order to indicate its 

 individuality. But these late researches show that these pro- 

 toplasts are not only highly organized and of complicated 

 structure, but each is bound by indissoluble ties to its nearest 

 neighbors, each helping to form a united whole. 



The fifth thesis has been completely controverted. In- 

 stead of believing, as formerly, that alf the granules within 

 the cell arise de novo from the protoplasm in which they are 

 imbedded, we are now forced to regard all of them as spring- 

 ing from pre-existent bodies of the same character. 



Hofmeister, in 1867, ^ an exhaustive description of the 

 contents of vegetable cells, states distinctly that the nucleus 

 arises from homogeneous protoplasm, and that in all cell 



