CHAPTER VIII 



THE FROG (continued) : THE MICROSCOPIC EXAMINATION 



OF THE COMPOUND " TISSUES GLANDS SECRETION 

 AND ABSORPTION 



WITH the exception of the tissues of the nervous 

 system, which will be described in Chapter X, we have 

 now studied the principal simple tissues by the method 

 of. dissociation, i.e., by separating their constituent parts. 

 We have now to consider the way in which these tissues 

 are combined in the various organs, and for this purpose 

 must adopt some method of examination by which they 

 are seen in their natural relations. 



The method adopted for this purpose is that of section- 

 cutting. You know how, by cutting sections, in various 

 directions, of a bit of twig, the arrangement and natural 

 relations of its various parts wood, bark, and pith can 

 be ascertained. The same thing applies to the organs of 

 the frog and other animals, but, owing to their soft and 

 non-resistant texture, it is impossible to cut them into 

 sections thin enough for microscopic examination with- 

 out special preparation. The methods employed are by 

 no means easy for the beginner, especially without 

 verbal instruction and the resources of a biological labora- 

 tory ; but in the event of your wishing to make the 

 preparations described and figured in this chapter for 



