170 The Microscope. 



covered that typical protoplasm, such as is found in young and 

 active cells, consists of the following substances, which henceforth 

 must be considered as essential elements in living matter : Al- 

 buminous matter (vitellin or myosin, at least) ; phosphoric mat- 

 ter (lecithin and nuclein) ; one or several hydro-carbonates 

 (glycose, dextrin, glycogen) ; soluble ferments (diastase, pepsin, 

 emulsin) ; water (of constitution and imbibition) ; mineral 

 elements (salts, sulphates, phospates, nitrates of K., of Ca., and 

 of Mg.)." 



Recently (1881) Reinke and Rodewald analyzed the Plasmo- 

 dium of JEthalium septicum, in which other elements besides the 

 above enumerated, have been found ; but possibly these were 

 only accidental. The microchemical researches of Zacharias, 

 1881-1888, have revealed a new element of a protein nature, 

 called plastin: and more recently even soluble ferments have 

 been discovered which are called coagulating ferments. These 

 ferments found in both animal and vegetable cells seem to be 

 necessary for the accomplishment of certain phenomena of cel- 

 lular life. But no doubt the most important work in micro- 

 chemistry is reserved for the future. 



Structure of the nucleus. — As far back as 1859 Stilling had 

 already called attention to certain zigzag, filamentous bodies in 

 the nucleus. Fromann believed the appearance to be caused by 

 strings and filaments crossing each other in their various rami- 

 fications ; Heitzmann considers them as mere condensations of 

 protoplasm ; and in 1867 Hertig calls them "nuclear substance,"' 

 and the hyaline substance between them he calls " nuclear sap."' 

 Flemming found however that these bodies form a real network, 

 called reticulum, and that it is this reticulum that is colored 

 particularly by staining fluids, which fact at once proves its non- 

 identity with the surrounding protoplasm, an observation which- 

 in our opinion is correct. In 1879 Flemming calls this substance 

 of the reticulum chromatin, and the part not affected by the- 

 same coloring reagents he calls achromatin. 



Miesher, in 1871 made an important discovery, which marks 

 an epoch in the history of the microchemistry of the nucleus y 

 he found in the cells of pus, a particular substance to which he 

 gave the name of nuclein, and also called attention to the most 

 noted properties of this substance. 



Prof Carnoy at once saw the importance of this discovery,. 



