THE FROG : HISTOLOGY, GERM CELLS, DEATH 87 



the body exists only to support and protect it. Life is 

 the life of protoplasm. 



It is sometimes attempted to recognise in protoplasm a 

 truly living part which undergoes relatively little change 



FIG. 46. — A portion of the section shown in Fig. 45, more highly 

 magnified. 

 b.v., Blood vessel ; c.t., connective tissue of mucous membrane ; c.m., circular 

 layer of muscle fibres; eg., epithelium; g.c, goblet cell; l.m., longi- 

 tudinal layer of muscle fibres; let., "lacteal" or lymph vessel of the 

 intestine ; leu., leucocyte of lymph or lymph corpuscle ; p.e., peritoneal 

 epithelium. 



and a part which is not truly alive, but undergoes the 

 changes which provide the bulk of the life energy, under 

 the influence of the living part acting as a kind of ferment 

 (p. 50). No doubt it is the case that there are many grades 

 of metabolism, but from the broad point of view it is better 



