HEREDITY 



47 



definite physical and chemical constitution is transmitted 

 to each of the daughter-cells; each, in other words, re- 

 ceives Pleurococcus protoplasm. This protoplasm, with 

 its definite organization, constitutes the inheritance. The 

 daughter-cells do not inherit a spherical shape (as is evident 

 from Fig. 33), but a definite kind of protoplasm, cell-sap 



FIG. 34. Pleurococcus vulgaris. Sections of one-, two-, and four-celled 

 plants, showing the nuclei and the large chlorophyll bodies (chb) to which 

 the green color of the plants is due. In D, the larger chloroplast is shown 

 in perspective. (Camera lucida drawings from a microscopic preparation 

 by E. W. Olive.). (Cf. Fig. 33.) 



of certain osmotic properties, and surface cellulose of even 

 elasticity, so that, in surroundings uniform on all sides, 

 a spherical shape must finally result. The shape is an 

 expression of the inheritance for the given environment. 

 Under different external conditions the expression might 

 be different; but the inheritance would be the same. The 

 chlorophyll in the daughter-cells, immediately after cell- 



