16 THE MICROSCOPE. 



determine the nature of various deposits wliich would be quite inscrut- 

 able to the naked eye. By this means it has been discovered that the 

 calcareous shelled foraminifera constitute a large proportion of the 

 chalk deposits, and that the silicious or flinty coverings of the diatoms 

 form extensive flinty deposits; and this is the way in which some 

 geologists account for the layers of flint in chalk formations, the pre- 

 sence of which was at one time a source of great speculation. The 

 whole city of Richmond is built upon a layer of infusorial earth 18 

 feet thick, and extending to unknown limits ; while the remains of 

 foraminifera form a band often 1,800 miles in breadth and of enormous 

 thickness, that may be traced from the Atlantic shores of Europe and 

 Africa through Western Asia to India and China, as well as over large 

 areas of North America. The material of which the pyramids are 

 built consists of remains of a species of foraminifera known as nummu - 

 lites. Indeed, minute fossil remains, often too small to be recognised 

 without the aid of the microscope, constitute no small portion of the 

 crust of the earth. The Greensand, for example, which underlies the 

 chalk, is composed chiefly of silicious casts of the interior of forami- 

 nifera and minute molluscs. And lastly, in the discovery of crime the 

 microscope plays no unimportant part. By its means many of the 

 vegetable poisons are detected ; and especially is it of use in deciding 

 whether stains are produced by blood or other fluids, for although the 

 blood discs bear a general family resemblance, there are marked 

 differences between the blood of man and some other animals. This 

 was well exemplified recently, where there was a train of circum- 

 stantial evidence pointing to the guilty man, and where, although 

 there was no moral doubt of his having committed the murder (he had 

 cut the throat of a young girl), there was just one legal link wanted to 

 complete the chain, which was supplied thus : the man had carefully 

 washed his clothes; no stain could be identified as blood; even the 

 knife found in his pocket had evidently been carefully wiped, but on 

 removing the blade a small dark-coloured mark was discovered in the 

 hinge, which being scraped off and placed under the microscope dis- 

 played unequivocal evidence of being blood ; nay, more, a few epithe- 

 lial cells peculiar to the lining of the air passages were also found 

 mingled with it ; and from this evidence the microscopist was not only 

 able to pronounce with certainty that the stain was blood, but that 

 the blood had flowed from the windpipe of a human being. 



And if you seek, reader, rather for pleasure than for wisdom, you 

 can find it in Nature, pmre and undefiled. Happy, truly, is the Natu- 

 ralist. He hath no time for melancholy dreams. The earth becomes 

 to him transparent ; everywhere he sees significancies, harmonies, laws, 

 chains of cause and effect endlessly interlinked, which draw him out 

 of the narrow sphere of self-interest and self -pleasing, into a pure and 

 wholesome region of solemn joy and wonder. — C. Kingsley. 



