16 



THE CAT. 



fCHAP. II 



is traversed by largo blood-vessels and by the alimentary tube, which 

 extends continuously from the mouth backwards to its posterior 

 termination. The parts of which the cat's body arc composed are 



Fij;. 2.— Diagram represkntino a Vertical Section through the Cat's Body. 



n. Brain and spinal niaiTOW contained witliin 

 tlie sknll and backbone, wliicli are det'ii 

 bUu;k. 



at. Breast-bone. 



dd. Aliiin'iitury canal. 



s. Stomach. 



/i. Heart. 



fc. (ireat blood-vessel.s. 



■H. Urinary bladder. 



s.i/. Chain of synii>athetic ganglia. 



dl. Diaphragm. 



thus conveniently divisible into the bones, with their membranes — 

 the .sh'Ho)i. ; the muscles ; the nervous system and organs of sense ; 

 the * system of vessels, or circulatory system ; the alimentary tube, 

 with its appendages ; the lungs and kidneys, with certain other 

 parts, and the organs of reproduction. 



THE SKELETON. 



§ 2. The word " d-ckton" is popularly taken to denote only the 

 bones, with the caytilage or gristle which may be connected with 

 them. It should, however, be taken to mean not only these but 

 also the membranes, which radiating from the bones and cartilages 

 invest every organ of the body, and finally clotlie it externally in 

 the form oi" " skin." Such membranes penetrate the very bones 

 themselves and support the marrow they contain ; they separate 

 every muscle from its neighbour, and surround and lino each tube 

 and passage in the body ; so that if every other tissue could bo dis- 

 solved away and yet this fibrous tissue be left, we should have 

 a coniph^tc outline model, as it were, of the cat's entire frame. 



^ 3. This substance, which is, as it were, the basis of the skeleton, 

 is formed of what is called coNNF/'rn'E tisstte, which consi.sts of a 

 mass of delicate white hbres imbedded in a structureless material or 

 " o-round substance ; " scattcu'cd through this are minute particles (jf 

 protoplasm, called " corpuscles," which are more or less rounded or 



