42 2 BIOLOGY AND HUMAN LIFE 



313. Materials for esthetic uses. Clothing is used partly for 

 ornament. Indeed, primitive peoples living in the tropics, where 

 they need no protection, adorn themselves with all sorts of 

 trinkets and decorate their bodies with paint. These things do 

 not agree with our own tastes ; yet much of our interest in 

 clothing is of exactly the same kind, and within certain limits 

 it is quite as proper for us to get pleasure out of this kind of 

 beauty as to get it from the natural beauty of the earth and the 

 changing sky, or from plant and animal forms ; and it is quite 

 as proper to apply our skill in increasing our own beauty and 

 that of our clothing and furniture as it is to paint a picture or 

 decorate china. So we get buttons and brooches and combs 

 from the shells of mollusks and reptiles (tortoise) and from the 

 bones and horns of mammals ; we make bright dyes from in- 

 sects (cochineal) as well as from many plants; and we use the 

 plumage of birds and the cocoons of the silkworm. 



The materials out of which we make our musical instruments 

 are chiefly woods of many kinds, and catgut (which is usually 

 calf gut) and horsehair, used in making violin bows. Many of 

 the devices that we use in playing athletic and other games are 

 made of plant and animal material. 



Closely related to the esthetic is our use of materials solely 

 for their taste or flavor. Thus, seasonings and spices are of no 

 value as food, yet they are satisfying and so worth having. 

 There is, of course, some danger in their excessive use, since we 

 may come to depend upon them to make our food palatable. 

 In the same class we would place various fruit flavors with 

 which we make the drinking of water more interesting, tea and 

 coffee, and perhaps also tobacco in various forms. 



314. Tobacco and smoking. The tobacco of commerce is made of 

 the leaf and stalks of Nicotiana tabacum, a member of the potato fam- 

 ily. This family includes the very useful tomato plant, the eggplant, the 

 belladonna, and the nightshade. Some of these plants produce more or 

 less violent poisons. Even the tubers of the potato, while they are still 

 green, contain a poisonous alkaloid. The alkaloid in the tobacco, fiicotin, 

 is also poisonous, whether taken into the stomach or injected into the 



