1915.] PUBLIC DOCUMENT — No. 31. 25 a 



j\Ir. Ruprecht shows that aluminum sulfate in culture solu- 

 tions has a very toxic action on clover seedlings if present in 

 quantity greater than forty parts per million, and that ferrous 

 sulfate if present in concentration above four parts per million 

 exerts a somewhat similar effect. He shows further that this 

 toxic effect can be overcome in large measure in dilute solution 

 by the use of calcium carbonate. 



His experiments appear to indicate that one of the principal 

 reasons for the failure of clover on plots fertilized with sulfate 

 of ammonia without lime is due to the fact that aluminum and 

 iron are to some extent brought into solution by the action of 

 the sulfuric acid of the ammonium sulfate. 



The report of the chemist calls attention to a number of im- 

 provements in chemical methods, especially in methods con- 

 nected with the examination of fats, which have been perfected 

 by Mr. Holland and Mr. Buckley. It makes brief reference 

 to the investigations of Professor Morse on the chemical com- 

 position of asparagus, and briefly presents the principal results 

 of some investigations in animal nutrition. 



It has been shown that vegetable ivory, in spite of its hard and 

 horny nature, appears to be to a considerable extent digestible, 

 and may be a food product of some value. 



The report gives the usual account of the results of the in- 

 spections of commercial fertilizers and food stuffs and the ex- 

 amination of Babcock glassware. 



The Botanical Department. 



The botanical department has published one bulletin during 

 the year, 'No. 156, " Electrical Injuries to Trees." This bulle- 

 tin gives important information on the following points: the 

 electrical resistance in trees ; the effects of alternating and of 

 direct currents ; the effects of lightning and earth discharges ; 

 and discusses methods of preventing injury from contact with 

 wires carrying electric currents. 



The report of the botanist calls attention to some of the plant 

 diseases which have been unusually common during the past 

 year. Among these the Rhizoctonia disease of potatoes is one 

 of the most serious. 



