394 CHEMISTBY. 



gives peculiar flavor to grape wines ? How much of this ether do wines 

 contain? 511. To what is the acidity of grape wines due? 542. What is 

 said of the amount of alcohol in wines ? 543. What is the first step in 

 making alcohol of starchy substances ? What is malt ? How is it made ? 

 544. Describe the process of distillation. 545. What is fusel-oil ? How 

 produced? 546. Explain the raising of bread by yeast. What other 

 means are employed to raise bread ? How much water is there in bread ? 

 What makes bread stale ? 547. What is ether ? What are its properties ? 

 For what is it used ? 548. How may compound ethers be regarded ? Give 

 the names and flavors of some of the so-called fruit essences. 549. De- 

 scribe the process of making ether. Explain the chemical reaction which 

 ensues. What is obtained by managing the alcohol and sulphuric acid dif- 

 ferently? 550. How is chloroform made? Of what composed? 551. 

 What is vinegar ? Why can not acetic acid be obtained from it by distil- 

 lation? How is it obtained by the chemist? 552. What is said of the 

 common mode of making vinegar ? What is the mother of vinegar ? What 

 are vinegar eels, and how are they produced ? State in full what is said 

 of the acetous fermentation in preserves. 553. Explain the chemistry of 

 sour bread. 554. Explain in full the chemical changes of the acetous fer- 

 mentation. In what two stages does this change take place? 555. De- 

 scribe and explain the quick mode of making vinegar. 556. How is 

 vinegar commonly adulterated, and how can the adulteration be detected ? 



CHAPTER XXXI. 



ANIMAL CHEMISTRY. 



557. Materials. The elements which enter into the com- 

 position of the various substances found in animals are the 

 same with those which compose vegetable substances. Wo 

 have first the four grand elements carbon, oxygen, hydro- 

 gen, and nitrogen. There are also chlorine, sulphur, and 

 phosphorus, and also the metals calcium, potassium, so- 

 dium, and iron. As in vegetables, so in animals, these ele- 

 ments never appear as elements, but always in combina- 

 tion. Thus we never have chlorine alone, but it exists in 



