282 THE LURE OF THE LAND 



THE CONTRIBUTIONS OF CHEMISTEY. 



Perhaps it would be well to illustrate by a few in- 

 stances how scientific training and scientific methods 

 have proved beneficial to an industry, and I do not know 

 of any more striking example than that great industry in 

 whose interest we are here to-day. I will cite first 

 what chemistry has done in working up the refuse of civ- 

 ilized life into useful products. One or two instances 

 of this will be sufficient. Take the case of bones. 

 Chemistry has shown that bones contain a large amount 

 of phosphoric acid. It also showed that this acid was 

 an essential constituent of plant life, especially of the 

 cereals. This was the beginning of a great industry. 

 Bones which before had been the pest and plague of 

 cities and towns were carefully collected, ground and re- 

 turned to the soil as a most valuable fertilizer. 



Chemistry also showed that the nitrogen of plants was 

 not taken from the nitrogen of the air, at least only in 

 small quantities by one family, of plants. On the 

 other hand, it appeared that nitrogen in the form of 

 ammonia was most readily absorbed. This led the way 

 to the guano beds and the cess-pools. What was be- 

 fore considered not only worthless but really noxious, 

 was now sought after to enrich the soil. It was 

 also discovered that plants did not assimilate organic 

 particles as such, but that all these had first to undergo 

 decomposition before they could be used as plant food. 

 This fact reconciled people to using as food, plants 

 grown with fertilizers that were most offensive to 

 thought and sense. 



You may macerate a growing potato in starch, it 

 will not absorb a single grain of it. You may soak the 

 growing cane in sugar, the juice will not be one whit the 



