THE ANIMAL CELL. 303 



an investigation of those tissues which are especially rich in cells, 

 and in which the cells can be more or less completely separated from 

 the underlying matrix and from other components which may be 

 present at the same time. This is especially true of the leucocytes 

 of the blood. As these bodies, moreover, are but little differentiated, 

 they may well serve as types of primitive cells. They are all 

 nucleated, and contain a varying amount of protoplasm, which in 

 some is capable of progressive movement. A limiting membrane, 

 as in most animal cells, does not exist. But it is generally supposed 

 that a meshwork of fine fibrils pervades the protoplasm, and that in 

 the meshes a more liquid portion is contained. This is termed the 

 hyaloplasm, in contradistinction to the more solid spongioplasm. In 

 some forms the protoplasm is apparently perfectly homogeneous, while 

 in others it is studded with numerous granules of variable size, which 

 execute more or less active oscillatory movements, which are spoken 

 of as the molecular movements of Brown. 



The reaction of the protoplasm is alkaline, while the nucleus 

 apparently contains no free alkali. This may be shown by staining 

 dried blood films with a solution of acid erythrosin in chloroform, 

 when it will be seen that the body of the cell is colored a bright red, 

 while the nucleus is not stained. The most intense reaction is 

 obtained with the protoplasm of the so-called lymphocytes. 



The granules which are found in certain forms of leucocytes are 

 apparently of an albuminous nature. According to their affinity for 

 acid, basic, or neutral dyes, they are termed oxyphilic, basophilic, 

 and neutrophilic, respectively. Fatty, mineral, or pigment granules, 

 which may be found in other animal cells, are usually not seen in 

 leucocytes. In the eosinophilic leucocytes, however, the presence of 

 iron can readily be demonstrated by microchemical methods. In 

 another form it seems to be present in all varieties of cells, and is 

 especially abundant in the nuclei. 



In the mineral ash we further find potassium, sodium, calcium, 

 magnesium, phosphorus, and chlorine, and it is to be noted that, in 

 contradistinction to the animal fluids, the cell contains a relatively 

 larger amount of potassium and phosphorus, while sodium and 

 chlorine are more abundant in the fluids. That the phosphates are 

 of prime importance in the life of the cell is now definitely 

 established, and Loew showed that in the spirogyra, for example, 

 growth and cellular division are greatly interfered with by their 

 absence. The importance of the phosphates is without doubt con- 

 nected with the presence of the nncleins in the nuclei /. e. f of 

 albuminous substances which, as we have seen, contain a relatively 

 large amount of phosphorus in organic combination. 



The protoplasm of the cell is very rich in water, and, in addition 

 to small amounts of mineral salts, consists essentially of albumins. 

 Some of these are albumins proper, but the greater portion by 

 far is represented by substances which belong to the proteid 

 group. It appears, moreover, that the traces of serum-albumin and 



