IN HYGIENIC PHYSIOLOGY. 151 



2. Wliat causes the hair to i( stand on end" when we 



are frightened ? 



(See Physiology, p. 53.) 



Many of the unstriated muscular fibers from the true skin 

 pass obliquely down from the surface of the dermis to the 

 under side of the slanting hair-follicles. The contraction of 

 these fibers erects the hairs, and by drawing the follicles to the 

 surface and drawing in a little point of the skin, produces that 

 roughness of the integument called "goose-skin," or Cutis Anser- 

 ina. The standing on end of the hair of the head, as the re- 

 sult of extreme fright, may be partly due to the contraction of 

 such fibers, as well as to the action of the occipito-frontalis 

 muscle. CUTTER. 



3. Why is the skin roughened by riding in the cold ? 



(See Physiology, p. 53 ; also Answer to Q uestion 2.) 



4. Why is the back of a washer-woman's hand less 

 water-soaked than the palm? 



The difference depends upon the relative abundance of the 

 oil-glands in different parts of the body. 



5. WJiat would be the length of the perspiratory tubes 

 in a single square inch of the palm, if placed end to end ? 



(See Physiology, p. 61.) 



The length of the perspiratory tubes differs not only in dif- 

 ferent persons but in different parts of the same body. Some 

 authorities estimate the average length at \ of an inch, while 

 others and, generally, later authorities give only -^ of an inch. 

 If we assume the former measurement, we have : 2,800 x in. 

 = 21^00 i n . = 58 ft. 4 in. If the latter, we have 2,800x T V in. 

 = Af$a in. = 14 ft. 7 in. 



6. JVTiat colored clothing is best adapted to all seasons ? 



(See Physiology, p. 67 ; Popular Physics, p. 260.) 



Light-colored clothing is cooler in summer and warmer in 

 winter. 



7. What is the effect of paint and powder on the skin ? 



(See Physiology, p. 62.) 



