8 N. H. Agri. Experimext Station [Bui. 296 



fertility of the soil or the type of fertilizer materials used. To illus- 

 trate, we have found that when mosaic tubers are planted on the one 

 hand in a composted soil high in plant food elements, and on the other 

 in a soil poor in essential food elements, but to which an 8-8-16 fertil- 

 izer was added at a rate equivalent to 1000 lbs. per acre, the cultures 

 grown at 20° C. are very dissimilar in appearance. The plants grown in 

 the poor soil to which commercial fertilizer was added possessed good 

 healthy dark green foliage without recognizable mosaic symptoms, while 

 the plants in the composted soil had light green foliage with characteris- 

 tic mosaic markings. 



Leaf-roll plants. The leaf-roll plants have almost completely iTin out. 

 The seed pieces of the cultures grown at 20° C. all decayed, while 56 per 

 cent of the cultures grown at 15° C. remained hard. Planting at 15° C. 

 seed obtained from leaf-roll plants grown the previous year at 20° C. 

 seems to be more injurious than the reverse operation, while the rate of 

 deterioration of plants grown at 20° C. and 15° C. respectively is approx- 

 imately the same. 



From the studies on the effect of place we expect to obtain information 

 that will be useful to the seed grower and table stock grower and permit 

 one to ascertain from a perusal of weather records v/hether or not a 

 given locality is suitable for seed growing. We are also accumulating 

 information of value regarding the effect of climate on the symptom- 

 atology of leaf-roll and mosaic. The work is in charge of 0. Butler. 

 {Purnell Fund) 



Bacteria Do Not Cause Ruptured Egg Yolk 



Results of our bacteriological study indicate that bacteria are not the 

 primary cause of ruptured egg yolk in New Hampshire flocks. In the 

 etiological studies plate cultures were made from the organs, peritoneal 

 fluid and yolk material of twenty birds with typical ruptured egg-yolk 

 condition. Plain agar, meat infusion agar and meat infusion blood 

 agar were used for isolation purposes, and the cultures were incubated 

 both aerobically and anaerobically at 37° C. Thirty strains of bac- 

 teria were isolated and classified into four different species on the basis 

 of their morphological, cultural and biochemical characteristics. These 

 organisms were similar to the types identified in our previous studies. 

 Pasteurella avicida could not be detected in any of the birds examined. 



Pathogenicity studies gave essentially the same results as were pre- 

 viously reported. None of the species, when injected intraperitoneally 

 into healthy laying birds, produced ruptured egg yolk. The work was 

 conducted by L. W. Slanetz and C. L. Martin. {Purnell Fund) 



Hemolytic Streptococci in Pasteurized Milk 



In the hope that the studies on hemolytic streptococci will lead to 

 the introduction and improvement in different methods of handling 

 milk, work on their prevalence and classification was continued by L. 

 W. Slanetz. Meat exi:-ract agar containing 1 per cent proteose peptone 

 and 5 per cent sheep's blood proved to be very satisfactory for the de- 

 tection and isolation of these bacteria. 



Thirty-five cultures of hemolytic streptococci isolated from pasteur- 



