THE CELL AND PROTOPLASM. 95 



(NH S ), and passing up through a large number 

 of members of greater and greater complexity, 

 all composed, however, chiefly of the elements 

 carbon, oxygen, hydrogen, and nitrogen. Our 

 chemists found that starting with simple sub- 

 stances they could, by proper means, combine 

 them into molecules of greater complexity, and 

 in so doing could make many of the compounds 

 that had hitherto been produced only as a result 

 of living activities. For example, urea, formic 

 acid, indigo, and many other bodies hitherto pro- 

 duced only by animals and plants, were easily pro- 

 duced by the chemist by purely chemical methods. 

 Now when protoplasm had been discovered as the 

 "physical basis of life," and, when it was fur- 

 ther conceived that this substance is a proteid 

 related to albumens, it was inevitable that a 

 theory should arise which found the explanation 

 of life in accordance with simple chemical laws. 



If, as chemists and biologists then believe, 

 protoplasm is a compound which stands at the 

 head of the organic series, and if, as is the fact, 

 chemists are each year succeeding in making 

 higher and higher members of the series, it is 

 an easy assumption that some day they will be 

 able to make the highest member of the series. 

 Further, it is a well-known fact that simple 

 chemical compounds have simple physical pro- 

 perties, while the higher ones have more varied 

 properties. Water has the property of being 

 liquid at certain temperatures and solid at 

 others, and of dividing into small particles (i.e. 

 dissolving) certain bodies brought in contact 

 with it. The higher compound albumen has, 



