414 ADVANCED PHYSIOLOGY 



Page 236. 1. If one holds the hand very near a piece of cold glass, 

 e.g. the window glass, moisture collects on the latter. This is insensible 

 perspiration. 



When the opportunity presents itself, each student should very carefully 

 weigh himself, follow this with very vigorous exercise during which per- 

 spiration is sensibly produced, and then weigh himself again. The amount 

 of loss will be the amount perspired, most of which was sensible perspira- 

 tion. 



2. The arrangement of the dermal papillae in rows, resulting in the fine 

 parallel lines on the hand, with special patterns particularly well seen 

 on the finger and thumb tips, is emphasized by use of a hand lens ; the 

 sweat glands open along the tops of these ridges. A class would be much 

 interested in making a series of " finger prints," obtained simply by press- 

 ing the finger or thumb tip on to a paper or glass which has been smoked 

 in gas or camphor flame. 



Page 242. Wet the finger and blow upon it gently. In spite of the 

 fact that the breath is warm, it will feel cool. This is because the air 

 current evaporates the water, and this uses up the heat of the finger. 



CHAPTER XVI 



Page 250. Throughout this study of the bones constant use should 

 be made of a good human skeleton and of as many separate bones as can 

 be procured. Interesting comparisons can be made with the skeletons of 

 the fish, frog, and bird. 



Page 254. A disarticulated skull, like that shown in Figure 125, should 

 be on hand for examination. 



Page 260. A fresh bone of some size, e.g. the humerus or femur 

 of a sheep or calf, should be examined in class. Cross and longitudinal 

 sections made with hand saw show essential structure. Dried bones do 

 not show periosteum or marrow to advantage. 



Rib bones of a sheep or pig show bone composition well. Either burn 

 in fire to remove animal matter, or place in hydrochloric acid (15-20%) 

 to remove mineral matter. 



Page 262. Microscopic sections of bone, cross and longitudinal, should 

 be shown through medium powers of compound microscope. 



Page 264. Any fresh bone from a joint is good for showing carti- 

 lage. Microscopic sections can be conveniently made from fresh material 

 (end of femur of frog, if none other is at hand) with hand razor ; mount on 

 slide in water or 1% acetic acid. 



