ANNUAL REPORT, 1947-48 27 



The eradication of scab with Puratized Agricultural Spray was again incom- 

 plete in 1947 and 1948. Used as a protectant spray, it has given very good scab 

 control on Mcintosh trees. The fungicidal action of this spray residue deposited 

 on glass slides is lost after 24 to 48 hours, indicating decomposition and the vola- 

 tile nature of the active principle. 



Scab eradication in 1948 was outstanding and striking with phenyl-mercuri 

 acetate (Fungicide No. H L 331, California Spray Chernical Corp.); phenyl 

 mercuri monoethanol ammonium acetate (Puratized B); and phenyl mercuri 

 formamide (Puratized 806) (Gallowhur Chemical Corp.). The striking fungi- 

 cidal action of these mercury sprays upon visible and incubating scab infec- 

 tion suggests that satisfactory control of this disease is possible with a belated 

 and curtailed schedule of applications. 



Miscellaneous Studies. (E. F. Cuba, Waltham.) 



Control of Seed Decay and Damping-off of Vegetable Seedlings by Seed-borne 

 Chemicals. The tests of this year have concluded the effort to determine the 

 best chemicals for the various kinds of vegetable seeds. Cuprous oxide, Semesan, 

 Arasan, Spergon, and Phygon have general use; and Semesan, Jr., Fermate, and 

 Zinc Oxide, special and limited application. Information is offered to the vege- 

 table industry in the Vegetable Seed Treatment Chart published bj' the Exten- 

 sion Service of the University. 



Contact Dermatitis Among Celery Farmers. Coincident with the introduction 

 of green Summer Pascal celery, many farmers have complained about dermatitis 

 on the hands and forearms from contact with this celery. Sensitive workers 

 develop dermatitis especially while harvesting and stripping celery in the field, 

 and contact with rotted and ripe celery is especially hazardous. Spoilage of 

 celery in the field is due to the bacterial soft rot organism Erwinia carotovoriis . 

 On an average, one-third of the white workers are infected. Colored workers 

 from the Bahama Islands and Jamaica are not sensitive. Numerous celery 

 growers were tested for sensitivity with healthy and rotted celery tissue, with 

 dextro-limonene oil extract of healthy stalks and leaves taken up in 9 parts of 

 persic acid, and with crude oil from stalks and leaves without dilution. Workers 

 sensitive to celery dermatitis in experimental tests gave positive reactions as 

 indicated by erythema, pruritis, ulceration, vesicles, induration, and maculo- 

 papular lesions. The injurious factor is ascribed to dextro-limonene, the oil in 

 the celery. 



This study was conducted in cooperation with Dr. John G. Wiswell, Dr. John 

 W. Erwin, Dr. Francis W. Rackemann, and Miss Lena L. Neri of the Massachu- 

 setts General Hospital, Boston. Some phases of the study require further re- 

 search for completeness. 



A report of the study has been accepted for publication by the American 

 Journal of Allergy. 



DEPARTMENT OF CHEMISTRY 



Walter S. Ritchie in Charge 



Factors Affecting the Vitamin Content of Milk and Milk Products. (Arthur 

 D. Holmes.) The two types of milk, cows' and mares', used in the four studies 

 that were completed during the past year were produced on the University farm 

 under normal conditions. With one exception, i.e., milk from a Palomino mare, 

 all the mares' milk was obtained from young Percheron mares. The cows* milk 



