October, '22] mccolloch: attraction of corn for chloridea 337 



These experiments indicate that odor may be an important factor in 

 attracting the moths to the corn plant, and that the subject is worthy 

 of further investigation. A total of 464 eggs was deposited on the 

 twines during the three years, and 79.1 percent were placed on the 

 treated ones. The same results were obtained regardless of whether 

 these twines were placed on com plants or on stakes removed from the 

 plants. Moths were observed on these "silks" at various times and 

 when on treated ones they behaved very much as when on com silks, 

 often spending som,e time there and depositing several eggs. On the 

 other hand, when they were on the check twines they appeared restless 

 and often left without ovipositing. The treated twines retained the 

 com silk odor for several days. 



The problem now resolves itself into a study of the composition of 

 com silk since the final interpretation of the results and the continuance 

 of the experiment are dependent on this knowledge. A survey of the 

 literature gives but little help on this point, since the constituents are 

 but indefinitely known, although com silk has long been recognized 

 officially in the United States as a drug under the names "Zea," "Maidis 

 stigmata" or "Corn silk." Insofar as the writer has been able to learn, 

 practically all of the analytical work on the composition of com silk has 

 considered it as a drug. 



Rademaker and Fischer^ made an approximate analysis of the drug, 

 com silk, and a simimary of the constituents which they found is given, 

 together with the m.ethods used in making the determination. (Table 

 IV.) 



Table IV.— Showing the Amount of the most Important Constituents of the Drug 

 Corn Silk, as found by Rademaker and Fischer 



Constituent Percent Method used 



Fixed oil • 5.25 Petroleum spirit extract 



Resin, Crystalline principle*, chlorophyll 2.25 Ether extract 



Resin, Crystalline principle*, chlorophyll 3.25 Alchohol extract 



Sugar, gum and extractive 19.50 Water extract 



Albuminoids, phlobaphane, etc 3.50 From alkaline solution 



Salts and extractive 5.50 From acid solution 



Cellulose 37.00 



Water 20.00 



*This crystalline principle was found to be maizenic acid. 



Hare, Caspari, and Rusby'^ state that "The only specific constituents 

 of com silk which are definitely known, and upon which its activity 

 may depend, are its resin and maizenic acid. The latter is crystalline 



^Rademaker, C. J., and Fischer, J. L., Proximate analysis of Stigmata maydis. In 

 Amer. Journ. Phar, Vol. 58, Fourth series, Vol. 16, pp. 369-370. 1886. 



^Hare, H. A., Casperi, C, and Rusby, H. H., The National Standard Dispensatory. 

 Lea & Febiger, New York, 2081 p., 1916. 



