94 BIOLOGY: GENERAL AND MEDICAL 



undifferentiated speck of protoplasmic jelly. This 

 shows us that the protoplasm or cytoplasm, as it is now 

 usually called, is the essential living substance. Many 

 attempts have been made to show that the cytoplasm 

 is of definite texture, but it is now pretty generally con- 

 ceded that it consists of a structureless matrix or clear 

 jelly, the hyaloplasm, in which certain granules, the 

 spongioplasm or polioplasm, are suspended. It is 

 because of the presence of the spongioplasmic granules 

 that cytoplasm almost invariably appears granular. 



The granules are of various quality, as is shown by 

 their diverse micro-chemical reactions. This is well 

 shown by an examination of human white blood cor- 

 puscles treated with a mixture of colors, such as make up 

 Ehrlich's, Biondi's, Wright's, Jenner's, or Romanowski's 

 stains. When a carefully prepared film of human blood 

 is stained with one of these reagents, we find the white 

 corpuscles showing certain variations that enable them 

 to be assigned to well-marked classes. Thus, about 70 

 per cent, show a cytoplasm rich in granules that have 

 assumed a purple color, and are known as neutrophilic 

 granules; about 25 per cent, are without granules and 

 are called hyaline cells, and the remainder are chiefly 

 made up of cells filled with coarse round granules that 

 stain a brilliant red color the eosinophile cells. 



It may naturally be inferred, and the inference is 

 probably correct, that these diversely reacting granules 

 are different in nature and function, though it has not 

 been determined what the office of the granules is. 

 Altman, who first described cytoplasm as granular, called 

 the granules bioblasts and conceived that they were the 

 actual source of the cell life; but his view has been 

 abandoned, and we now suppose that the granules of 

 the spongioplasm are composed of those substances 

 formed by the living substances and useful in its 

 various activities. From this point of view these 

 granules are not permanent structures, but appear and 

 disappear as they are prepared or employed. 



