XI PHENOMENA OF ORGANIC NATURE 307 



useful to us in the performance of those services 

 in which we employ him. 



And then, on separating and removing the whole 

 of this skin and flesh, you have a great series 

 of bones, hard structures, bound together with 

 ligaments, and forming the skeleton which is 

 represented here. 



In that skeleton there are a number of parts to 

 be recognised. The long series of bones, beginning 

 from the skull and ending in the tail, is called the 

 spine, and those in front are the ribs ; and then 

 there are two pairs of limbs, one before and one 

 behind ; and there are what we all know as the 

 fore-legs and the hind -legs. If we pursue our 

 researches into the interior of this animal, we find 

 within the framework of the skeleton a great 

 cavity, or rather, I should say, two great cavities, 

 one cavity beginning in the skull and running 

 through the neck-bones, along the spine, and 

 ending in the tail, containing the brain and the 

 spinal marrow, which are extremely important 

 organs. The second great cavity, commencing 

 with the mouth, contains the gullet, the stomach, 

 the long intestine, and all the rest of those internal 

 apparatus which are essential for digestion ; and 

 then in the same great cavity, there are lodged the 

 heart and all the great vessels going from it ; and, 

 besides that the organs of respiration the lungs : 

 and then the kidneys, and the organs of repro- 

 duction, and so on. Let us now endeavour to 



