28 University of New Hampshire [Sta. Bui. 330 



were found to favor maximum toxin production. Alpha toxin was 

 found to be inactive by heating at 80°C for one-half hour. Beta 

 toxin resisted heating- at 80°C for 30 minutes and, in some cases, was 

 not inactivated at a temperature of 100°C for 30 minutes. A number 

 of strains of staphylococci from cases of staphylococcal mastitis pro- 

 duced enterotoxin. 



Methods were developed for the isolation of staphylococcus bac- 

 teriophage from milk. A pour plate technique using semi-solid agar 

 (0.5 to 0.8 per cent) was devised, which facilitated counting and 

 morphological study of phage plaques. Milk samples from a herd of 

 20 cows showing evidence of staphylococcus mastitis were exam- 

 ined and staphylococcus phages were isolated from 7 of the 20 cows. 

 The bovine phages isolated were similar to phages from human 

 sources in most respects. All attempts to show specificity of lysis 

 failed completely; phages from milk lysed staphylococci of both bo- 

 vine and human origin and phages from human sources did likewise. 

 There was no correlation between susceptibility to lysis and biochemi- 

 cal or toxin-producing characteristics. 



{Purnell Fund) 

 BOTANY 



Effects of Soil Moisture and Fertilizer Placement on the Vitality of 

 the Potato Seed Piece (Stuart Dunn) 



Seed pieces from the distal end of potato tubers were grown in 

 sandy loam at two temperatures (20.3°C and 13.8°C), and at three soil 

 moisture contents (50, 60, and 70 per cent of saturation). Fertilizer 

 treatment for each consisted of (a) no fertilizer, (b) 21 grams per 

 plant (750 lbs. per acre) spread in a circular band 21 inches wide and 

 ^2-inch distant from the seed piece, and (c) 14 grams of fertilizer 

 spread as in (b) above. 



Results of the experimental work show that rate of emergence 

 from soil was not particularly influenced by the treatments. Rate 

 of growth, however, was greater for the fertilized plants, and the re- 

 sponse of plants to fertilizer was more pronounced in the cold than 

 in the warm temperature. 



A station circular on this project, to be published early in 1941, 

 will summarize the results for the five years of experimentation. 



{Adams Fund) 

 A Study of the Causes of Injury by Lime-Sulphur Sprays (O. 'Butler) 



In the experiments performed during the year, a study was made 

 of the rate of recovery of the bean from lime-sulphur spray injury. 

 The plants were sprayed three times at 7-day intervals and harvested 

 7 days, 21 days, and 28 days after the last treatment. While the re- 

 sults secured show some variation, the plants have always recovered 

 following spraying. Several lots of plants were also sprayed with 

 y 2 per cent and 1 per cent flotation sulphur, the former being found 

 more injurious than the latter. In some trials, the flotation sulphur 

 sprays were found to be more injurious than the lime-sulphur sprays, 

 while in other instances they were less injurious. 



{Adams Fund) 



