56 The Microscope. 



former reminding one of a long corridor or gallery 

 with numerous recesses on either side, while the latter 

 would be represented by sundry glass cases filled with 

 valuables, standing at regular intervals on its floor, 

 and inserted in its walls. You will also see that the 

 dots of pigment in the finer hairs also are placed 

 between the strongly-marked " beads " instead of 

 within them ; and the mention of these finer hairs 

 brings us to another question often asked by ob- 

 servers, Why has the same animal apparently so 

 great a variety of hairs ? For instance in the otter's, 

 we see a large yellowish hair with brown centre, a 

 transparent hair with lengthened scales, and three 

 very small chain-like hairs. And human hair is of 

 many different diameters. 



This apparent variety of size, which happens to 

 add a good deal to the effect of a group of hairs as 

 seen with high magnifying powers, is caused by three 

 different circumstances. Firstly, many animals have 

 two kinds, namely, firm and long hairs, and fine down. 

 Secondly, many hairs are somewhat flat, and therefore 

 look narrowest when seen edgewise. Thirdly, the 

 hairs of many animals are differently formed in dif- 

 ferent parts of their length. 



The next remark may be that the distinctions of 

 rind and pith do not seem to hold good with all the 

 hairs. True enough ; and this sort of variety meets 

 us in many natural history researches. A general 

 rule is stated, and then the words "frequently," 

 <f commonly," or, as the old adage has it, ' f almost 

 and very nigh," have to be put in to prevent mis- 



