30 



ACTION OF ANIMALS. 



Silica 



Lime 



Magnesia 



Oxide ot'irou . 



Oxide of manganese 



Loss 



47-0 

 11-3 



7-3 

 20-0 

 10-0 



4-4 



Mr. Children, in his valuable notes to Berzelius, 

 describes a specimen from Taberg, near Philipstadt, 

 as consisting of one atom of trisilicate of lime, and 

 three compound atoms of bisilicate of magnesia and 

 protoxide of iron. 



The common actinolite occurs in a variety of forms, 

 and is found in great beauty at Loch Eil in Inverness, 

 and in the neighbourhood of lledruth, Cornwall ; it is 

 also common in the northern parts of Europe. 



The glassy actinolite is usually of a mountain green 

 colour. It occurs in primitive rock in the Isle of 

 Skye, and in various parts of Europe and Asia. 

 ' ACTION OF ANIMALS. The action of ani- 

 mals is a subject of the greatest interest, not only as 

 displaying that beautiful harmony of orgam'sation and 

 purpose which is conspicuous throughout the whole of 

 living nature ; but because, in the organs of animals, 

 and the actions which they perform, we find the most 

 perfect models for the various species of machinery 

 employed by human ingenuity. Their actions 

 must be considered as threefold, or depending upon 

 three distinct sets or systems of principles or laws. 

 In the first place, as the body of the animal is matter, 

 it must obey the mechanical laws of matter ; so that 

 neither the whole, nor any part of it, can move with- 

 out the exertion of a force sufficiently powerful to 

 overcome the resistance of inertia and gravitation. 

 A finger cannot be stretched or bent, an eye cannot 

 twinkle, or adapt its focus to an object at a dif- 

 ferent distance, without an effort as much greater than 

 the result as is sufficient to overcome the inertia of 

 the organ. This effort must have a certain magnitude 

 before we can feel it, just as all objects of the senses 

 must have a certain magnitude before we can perceive 

 them ; but as we can virtually analyse the object of 

 sense down to the ultimate atom which cannot be sup- 

 posed to become less, so can we analyse the effort 

 down to its minimum. But in many cases we feel 

 fatigue, either from the intensity of the effort or from 

 its continuance ; so that standing with the feet close, 

 the body erect, and one arm down by the side, we feel 

 the keeping of the other arm horizontally stretched, 

 for even ten minutes, more fatiguing than if we 

 allowed the body its natural play and carried a hun- 

 dred weight for the same time. It cannot be the 

 matter in the body which thus becomes fatigued? 

 The stone never tires in lying on the ground ; the 

 planet in its orbit (though tne motion, in the case of 

 the earth, is more than sixty thousand miles in the 

 hour) is never fatigued, or requires rest. That which 

 gives the effort is fatigued and exhausted by giving it, 

 and fails in being able to give it beyond a certain 

 limit ; it is not matter, but something which, to a certain 

 extent, controuls and overcomes the ordinary proper- 

 ties of matter, whether that matter be in the body of 

 an animal, or in something external of it. This power 

 of overcoming the laws of inanimate matter is what 

 we properly term animal power ; and the result of it, 

 the only means that we have of judging of the power, 

 or knowing of its existence, is animal action. 



But, secondly, the animal power ceases to act, if it 

 is not accompanied by certain chemical changes, the 

 occurrence of which, in opposition to the ordinary 



chemical action of inanimate matter, proves that it too 

 is the result of animal power. The chemical combi- 

 nation of the I'oodj be that food what it may, must be 

 wholly changed by the process of digestion ; new 

 matter must lie added to all the parts of the body, and 

 \hat which is no longer fit for the purposes of life (the 

 waste and rubbish as it were) must be removed out of 

 the system, by various external avenues, and generally 

 from the internal and more delicate parts, by the 

 action of the air upon the blood and of the blood 

 upon the air, in the operation of breathing. It has 

 often been poetically as well as popularly said, that the 

 air in this operation is the life ; and even those who 

 might have been expected to write advisedly at least on 

 the subject have gone into arguments to prove that the 

 air is really a vital fluid, that it is the source of animal 

 /teat, and the preserver if not the fountain of animal 

 life ; but truly there is no vitality in the air, or in any 

 component part of it, neither is there in any <me sub- 

 stance a store of heat, or of any other energy, sub- 

 stantireli/ accumulated, and producible without, the 

 action of something else. The breeze would play long 

 enoutrh over the pasture, ere it awakened the most 

 kindly herbage into sheep ; and the storm might rage 

 for ever among the mountain crags, without animating 

 these crags into eagles. The natural action of the air 

 is to cool that against which it beats;' the air which is 

 discharged from the lungs is warmed as well as 

 changed ; and if that which is received into the lungs 

 is so nearly of the same temperature with the body 

 as to exert no cooling influence there, the breathing of 

 it is always unwholesome and laborious. The heat and 

 the chemical changes which take place in the living 

 body, like the mechanical action of that body, take 

 place in opposition to what would be the state ofthingl 

 around if life were not there ; and when life is extinct, 

 the matter over which it held controul is yielded up 

 to the common laws of matter : the body falls prone 

 on the ground in obedience to the law of gravitation, 

 and it decomposes and moulders in obedience to the 

 laws of chemistry, with a rapidity proportional to the 

 intensity of their action. . 



The power which the animal has of controling the 

 mechanical and the chemical laws of matter bcirin, 

 increase, fade, and cease together ; and while they 

 remain in action, every effort of the one is followed, 

 or rather we may say, contemporaneously accompanied 

 by a similar effort of the other. The power in the one 

 animal is therefore one power the physiologic power 

 the power of life, of which, from the very nature of 

 things, we can know nothing further than we are able 

 to infer from the results of its action, which is, 

 indeed, all that we can know about power of any 

 kind. 



Of the chemical actions of animals we can know 

 but little, or rather nothing ; for chemical action is 

 between particle and particle, even in dead matter, 

 and the result even there is always mechanical before 

 we can observe it ; therefore, in speaking of the action 

 of animals as a subject, of rational and useful, and even 

 of entertaining knowledge, (for that which has no 

 meaning cannot entertain much or long,) we must 

 confine ourselves to their mechanical action. Even 

 there, we must exercise some caution in order to see 

 clearly the beauty of the subject, and to learn suc- 

 cessfully those practical lessons which it can so abun- 

 dantly furnish. 



When it is said that the power of life in an animal 

 opposes or counteracts the common laws of mechanics 



