90 DR. LOUIS ELSBERG. 



compact projections, either globular or elongated, the first 

 differentiation consisting in the occurrence of a central vacuole, 

 while after a certain development has been attained the plant 

 protoplasm appears in the form of a network. 



Many botanists have observed and described reticulated 

 living matter, not only when in its naked condition, as Plas- 

 modium, as it is called, but also when enclosed in a cellulose 

 wall. Allow me to cite a few examples : Sachs has figured "a 

 cell of Zygnema cruciatum, with two stellate chlorophyll- 

 bodies which are suspended in the interior of the cell; they are 

 united by a colourless bridge of protoplasm in which lies a 

 nucleus ; the rays which form the union with the parietal sac 

 are already nearly colourless in the middle. In each of the 

 two chlorophyll-bodies lies a large grain of starch (amplifica- 

 tion 550)," also " forms of the protoplasm contained in cells of 

 Indian corn (Zea mais) ; a, cells from the first leaf-sheath of a 

 germinating plant, showing the frothy condition of the proto- 

 plasm, i.e. the many vacuoles separated by thin plates ; b, cells 

 from the first internode of the germinating plant ; the proto- 

 plasm is broken up into many rounded masses in each of 

 which there is a vacuole (b) ; these are the so-called ' sap- 

 vesicles.'" Sachs has also figured "parenchyma cellsfrom the 

 central cortical layer of the root of Fritillaria imperialis, 

 longitudinal sections, A, very young cells, lying close above the 

 apex of the root, still without cell sap or vacuoles, b, cells of 

 the same description about 2 millimetres above the apex of the 

 root; by the entrance of cell sap the vacuoles s, s, s, have 

 been formed, c, cells of the same description about 7 to 8 

 millimetres above the apex of the root," in one of which the 

 reticulum is very plainly seen. Bessey says " in the stamen- 

 hairs of Tradescantia Virginica the protoplasm forms a 

 rather thick layer over the inner surface of the cell wall, and 

 in some part of this layer the nucleus lies embedded. From 

 the nucleus, and from various parts of the protoplasmic layer, 

 there pass to the opposite side of the cell thicker or thinner 

 bands and strings, and gives a figure of the same after Hof- 

 meister. Prantl has fi^^ured Meristem cells of the stem of 



