DIFFERENT KINDS OF CELLS. 28 



physical phenomena of the organism, as well as the tissues 

 which are its seat. Then we shall consider the blood globule 

 and its circulation, and finally, prepared by our knowledge of 

 the accessories, we can more readily comprehend the more 

 intricate relations of the internal and external coverings, and 

 especially the epithelium of the genital organs, as well also 

 as our point of departure, the ovuin. 



