OF ORGANIC NATURE 13 



Few animals can be more familiar to you than that 

 whose skeleton is shown on our diagram. You need not 

 bother yourselves with this " Equus caballus " written 

 under it ; that is only the Latin name of it, and does not 

 make it any better. It simply means the common Horse. 

 Suppose we wish to understand all about the Horse. Our 

 first object must be to study the structure of the animal. 

 The whole of his body is inclosed within a hide, a skin covered 

 with hair ; and if that hide or skin be taken off, we find a 

 great mass of flesh, or what is technically called muscle, 

 being the substance which by its power of contraction 

 enables the animal to move. These muscles move the 

 hard parts one upon the other, and so give that strength 

 and power of motion which renders the Horse so 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 

 recognized. 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, con- 

 taining 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 reproduction, and so on. Let us now 

 endeavour to reduce this notion of a horse that we now 

 have, to some such kind of simple expression as can be at 

 once, and without difficulty, retained in the mind, apart 

 from all minor details. If I make a transverse section, 



