LAW; ITS DEFINITIONS. 95 



been revealed by any science. They are laws of 

 great exactness, having invariable relations to 

 number and proportion. Each elementary sub- 

 stance has its own combining proportions with 

 other elements, so that, except in these propor- 

 tions, no chemical union can take place at all. 

 And when chemical union does take place, the 

 compounds which result have different and even 

 opposite powers, according to the different pro- 

 portions employed. Then, the relations in which 

 these inorganic compounds stand to the chemistry 

 of Life, constitute another vast series in which the 

 principle of adjustment has applications infinite 

 in number, and as infinite in beauty. How deli- 

 cate these relations are, and how tremendous are 

 the issues depending on their management, may be 

 conceived from this single fact, — that the same ele- 

 ments combined in one proportion are sometimes a 

 nutritious food or a grateful stimulant, soothing and 

 sustaining the powers of life; whilst, combined in 

 another proportion, they may be a deadly poison, 

 paralysing the heart and carrying agony along 

 every nerve and fibre of the animal frame. This 

 is no mere theoretical possibility. It is actually 



