82 Human Physiology. 



any race of creatures committed to our care, and for whose 

 welfare and happiness we were held responsible by a higher 

 power. 



Man, in his physical body, is composed of matter, subsists 

 on matter, is subject to material laws and conditions; therefore 

 we must try to understand something of matter to see, at 

 least, how wonderful a thing it is, and to know how little is 

 known, and probably can be known, about it 



It seems to be proved by spectrum analysis that the whole 

 visible universe, all the stars that sprinkle the firmament, and 

 the millions that the telescope reveals to us, with all their 

 attendant planets, are composed of the same kind of matter 

 that forms our own solar system. Universal analogy is the law 

 of creation ; and there can be little doubt that all the worlds of 

 the universe are full of vegetative and animal life. 



This matter of which all worlds are made seems to us a 

 greater mystery than mind, of which we are conscious. We 

 think and feel, and know something of our thoughts and feel- 

 ings ; but of matter, beyond the impression it makes upon our 

 senses, we know so little that many have doubted the existence 

 of any matter of anything but ourselves and our sensations. 

 Such philosophers must, of course, believe only in themselves. 

 All other persons, like all other things, are sensations only ; and 

 the mother is not sure of the material reality of the babe on 

 her bosom. 



Matter exists in the visible and tangible world about us in 

 three forms solid, liquid, aeriform or gaseous ; as rock, water, 

 air. But the same matter may take all forms, as ice, water, 

 steam, or the invisible vapour of water dissolved in the atmo- 

 sphere, condensed at times into visible clouds, rain, snow, or 

 hail. So mercury, a liquid metal, congeals into a lead-like 

 solid, or turns to vapour with sufficient heat. So gases can 

 be compressed into liquids, and then into solids. Most simple 

 substances take on these three forms of matter. 



