444 



SCIENCE. 



[N. S. Vol. II. No. 40. 



Not of less practical importance to agri- 

 culture has been the recent progress in our 

 knowledge of that indefinite complex which 

 has so long passed under the misnomer of 

 ' nitrogen-free extract. ' With the exception 

 of the facts that it is not nitrogen-free and 

 that it is not au extract, the name may do 

 well enough. At least some agricultural 

 chemists have au idea of what the term 

 signifies, and to others it serves the purj^ose 

 of the phj'siciau's malaria, permitting them 

 to designate, in a fairly mysterious way, a 

 something of which nothing is known. The 

 constitution of the greater part of this com- 

 plex body is now known, and the propor- 

 tions of cellulose and of pentosans which 

 it contains can be determined with a fair 

 degree of definiteness. We should deem it 

 a matter for congratulation to be assured 

 that the day is fast approaching when the 

 agricultural chemist will no longer be called 

 on to determine forty per cent, or more of 

 a cattle food ' by difference.' 



In late years not only has organic chem- 

 istry helped us in the way of a better un- 

 derstanding of the composition of the carbo- 

 hydrates, but it has also pointed out to us 

 some of the main points in the constitution 

 of those most valuable products, the vege- 

 table proteids. We are far behind our 

 digestive organs in our understanding of 

 these bodies and have been accustomed in 

 practical work to place all proteid matter 

 together in a single class. But there is no 

 doubt of the fact that the vegetable pro- 

 teids differ as much among themselves as 

 those of animal origin, and at last the 

 chemist is able to distinguish between 

 them. Even if it should prove that there 

 is little difference in their food value, yet it 

 must be conceded that a knowledge of their 

 structural differences, together with the 

 several contents of nitrogen found therein, 

 will prove in the end of the greatest advan- 

 tage to the agricultural cliemist. 



The relations of agriculture to pedagogic 



chemistry have already been mentioned. 

 In many of our public schools it is thought 

 to be quite as important to teach the child 

 something about the life of the field and 

 the orchard as to drill him in the geogra- 

 phy of Johore. How plants and animals 

 grow is a theme which will one day be de- 

 veloped in every school in the land. N"atu- 

 rally, in agricultural colleges, the pedagogic 

 side of agricultural chemistry receives due 

 consideration, but alas ! with. these institu- 

 tions it is sometimes nomen et pneterea nihil. 

 In these cases agricultural chemistrj^ must 

 often give place to a heterochronistic psj'- 

 chology. But, on other hand, many of our 

 universities have recognized the need of 

 such instruction and have provided properly 

 therefor. Merelj' material considerations 

 should induce all our higher institutions of 

 learning to provide for advanced instruction 

 in agricultural chemistrj^, for'ju.st now there 

 is, and for years to come there will be, a large 

 demand for j'oung men well trained in this 

 direction. It will not be many years before 

 it will be required of everj^ well-equipped 

 university to provide liberally for the pro- 

 fessional education of the young men who 

 are to take charge of the agricultural col- 

 leges and experiment stations of the conn- 

 try. 



In its relations to bacteriologj'^, agricul- 

 tural chemistry is also a debtor. In the 

 life history of those minute vegetable or- 

 ganisms \vhich exert so profound a chemi- 

 cal action on many bodies has been found 

 the solution of the problem of those fer- 

 mentations which prepare for use the nitro- 

 genous foods of plants. The successive 

 conversion of organized nitrogen into am- 

 monia, nitrous and nitric acids is a process 

 of the most vital importance to plant life. 

 It is true that these activities were exerted 

 for several millions of years without our 

 knowing anything about them, and they 

 would doubtless go on until the end of time 

 if our knoMledge of them should entirely 



