CHAP. I.] INTIWDUCTOBY. 9 



fore embraces wltliin it both zoologi/ and hotauy. Moreover, Biology 

 not only includes these t\YO subordinate sciences, but also the various 

 inquiries vrliich refer to the relations which exist between their 

 respective subject-matters. 



Now, in the first place, the study of the cat, as of every living 

 creature, may bo followed up along two different lines of inquiry. 

 One of these refers to the structure of its bod}^, the other refers to 

 the actions which its body performs ; in other words, the animal 

 may be considered statically or dynamically. 



Before, however, considering these two kinds of inquirj^ and 

 seeing what subordinate inquiries they respectively include, it may 

 be well to note that the cat's body is obviously a complex structure, 

 consisting of distinct parts, which arc also obviouvsly put to different 

 uses, and reciprocally minister one to another. Thus, for example, 

 the limbs may more or less rapidly propel the body after prey which 

 the eyes guide the paws to grasp and bring to the teeth and jaws 

 by which it is divided to pass into the interior of the trunk, to be 

 there converted by the digestive organs into nutriment, by which 

 the limbs, the eyes, the paws, the teeth and jaws, stomach, intes- 

 tine, &c., are themselves supported and maintained in healthy 

 working condition. This animal's body, then, is a complex icJioIc in 

 ichich all the parts are reclprocalhj cmh and means ; and such is the 

 definition of " an orgais'Ism," wide as is the difference in complexity 

 between organisms, both animal and vegetable, of very different 

 kinds. 



§ 9. The organism with which we are occupied, the cat's body, 

 may, . as has been already said, be considered as to its structure 

 and as to its actions. As to its structure it may be considered with 

 respect to its size, shape, consistency, the number, form, and relative 

 position of its various parts, and such study is called Anatomy. The 

 inquiry as to its form is called Mo)pJtoIogij, and this inquiry may 

 be directed to its larger parts and grosser structures or to its minute 

 structure. 



The various parts of the cat's body, such as its tongue, ej'^es, 

 stomach, kidneys, &c., are termed " organs," and these arc grouped 

 together into different "sets" or "systems." Thus, e.g., we have 

 the alimentary system of organs made up of the mouth, oesophagus, 

 stomach, and intestine — or alimentary tube — with the various organs, 

 liver, pancreas, &c., which are directly connected with that tube. 

 But every organ is made up of several different animal substances, 

 variously blended, and differing in their minute or microscopic 

 characters. The study of such minute structure — such microscopic 

 anatomy — is termed Histologij. Each of the various substances 

 thus minutely differing, and which build up the organs of the body, 

 is called a tissue, and Histology is, therefore, the science of the 

 tissues of which every living creature may be composed. Histology 

 enables us to understand the structure and nature of the ultimate 

 substance or jMrenchi/nia of the body, as far as our powers of observa- 

 tion at present extend ; but those powers are very imperfect, and 



