THE MICROSCOPE 327 



varies, and it is chiefly by reason of the differences in the com- 

 bination of these associations in various degrees, that each 

 species possesses the anatomical properties and characters 

 which are peculiar to it." 



19. Hence the butcher's stall will furnish all the materials 

 for the study of the microscopic tissues. The structure of the 

 heart, lungs, liver, brain, and muscle, may all be studied, and 

 well studied, by using minute pieces of the flesh of the lower 

 animals, especially of the quadrupeds. Such portions of these 

 animals as are not exposed for sale can be readily obtained by 

 order from the slaughter-house. To examine with the powers 

 of which we have been speaking, it is only necessary to cut off 

 exceedingly small pieces, tear them apart with needles, or make 

 very delicate sections with a sharp knife. 



20. Incentives to Study. A complete knowledge of all 

 minute structures is not to be expected at once, for you are 

 here introduced into a new realm of Nature, a world of little 

 things as vast, as wonderful, and as carefully constructed as 

 the starry firmament that other realm of grand objects which 

 the astronomer rightly scans with the telescope. It will not 

 appear singular, therefore, if, at first, you feel strange and 

 awkward in this new creation. With a little perseverance, 

 however, and with the attention directed towards simple ob- 

 jects at the outset, it will not be long before an increasing 

 experience will engender confidence. 



21. If to all this there be added an enthusiastic study of 

 the standard authorities on the subject, the rate of progress 

 will be much more rapid. As compared with similar studies, 

 few possess more interest than microscopy, and to the one who 

 pursues it with fondness, it constantly affords sources of pleas- 

 ure and agreeable surprises ; and in the end often leads to new 

 and valuable additions to the sum of human knowledge. The 

 depths which the microscope is employed to fathom are no 

 more completely known than are the heights above us explored 

 and comprehended by the astronomer. 



19. How to procure materials for the study of the tissues of man :- 



