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JOURNAL OF THE [April, 



tainly gains support from the fact that vegetable histologists are 

 pretty well agreed that a more or less similar reticulum is demon- 

 strable in the protoplasm of plants. Professor Goodale seems 

 to have no doubt on this point, although he thinks that "this 

 conception of protoplasm as a mass composed of a net-work of 

 minutest fibres enclosing in the meshes another substance, pre- 

 sents * * * * great difficulties when we endeavor to explain 

 the movements within the cell;" and that " it is very difficult 

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

 outside the cell-wall or into intercellular spaces." 



Doctor Heitzmann, however, considers the reticulum or mesh 

 an easy explanation of protoplasmic movements. To him the 

 net-work of living, contractile matter contains in its interstices a 

 lifeless liquid, which, by its contraction, it is able to squeeze 

 out of itself, or from one part to another. Thus, he says, " the 

 liquid held in the meshes, being driven out of the contracted 

 portion will rush into a portion at the time at rest, and will 

 extend this portion in the shape of what has been termed 

 pseudopodia."*' 



In the work from which I have just quoted, Doctor Heitz- 

 mann generalizes as follows : " What * * * * was called a 

 structureless, elementary organism, a ' cell,' I have demon- 

 strated to consist only in part- of living matter, while even the 

 minutest granules of this matter are endowed with manifesta- 

 tions of life. The cell of the authors, therefore, is not an ele- 

 mentary, but a rather complicated, organism, of which small de- 

 tached portions will exhibit amoeboid motions. * * * * How 

 complicated the structure of a minute particle of living matter 

 may be, we can hardly imagine ; what we do know is that the 

 so-called ' cell ' is composed of innumerable particles of living 

 matter, every one of which is endowed with properties formerly 

 attributed to the cell-organism." 



It having been shown that life hangs upon a web of infinite 

 tenuity, and does not reside necessarily in either a vesicle or a 

 lump, it was a natural and easy step to extend this net-work 

 from tissue to tissue and organ to organ, in an unbroken circuit 

 of vital communication. This step Doctor Heitzmann does not 

 hesitate to take ; for, says he, " there is no such thing as an iso- 

 lated, individual cell in the tissues, as all cells prove to be joined 



21 " Microscopical Morphology." New York, 1883. 



