30 N. H. Agr. ExPERlMENt Station [Bulletin 304 



Fertilizer Placement with Potatoes 



Distribution of fertilizer in bands at one-half inch distance or even 

 contiguous to the potato seed piece was not found to interfere with 

 sprout emergence in studies made by Stuart Dunn. The sprouts from 

 the fertilized seed pieces emerged at the same mean rate as the sprouts 

 from the non-fertilized seed, confirming previous experience. The rate 

 of emergence of the sprouts from the distal seed pieces was more rapid 

 than from the basal pieces, but the weekly growth rate declined sooner 

 in the former. Tuber set was greatly increased and equally in the case 

 of both series of fertilized plants and was not affected by the tempera- 

 ture at which the potatoes were grown. Tuber yield was greatly in- 

 creased by the fertilizer, there being no noticeable difference due to 

 amount used in the case of the plants grown at 20° C, but in the cul- 

 tures at 15° C. the results obtained were irregular. {Adams Fund) 



Leaf -Roll Potatoes Deteriorate 



After eight successive years no evidence is available of the loss of 

 productivity of potatoes effected with mosaic, reports 0. Butler, but 

 leaf -roll plants have grown less productive from year to year and the 

 last remaining ones failed to produce a single tuber large enough to 

 make two seed pieces. {Purnell Fund) 



Study of Bovine Mastitis 



In studies of diagnostic tests for mastitis L. \Y. Slanetz reports that 

 the blood agar plate, and the microscopic test have given the best re- 

 sults to date, although it has been found difficult to make an accurate 

 diagnosis using only one test. The Burri slant method gave results com- 

 parable with the blood agar plate and the microscopic test, but was not 

 as satisfactory for general purposes as the former. The strip-cup and 

 brom thymol blue tests only detected animals in more advanced stages 

 of infection. 



Three hundred and fifty strains of streptococci have been isolated 

 from infected cows and approximately 90 per cent, of these strains have 

 been tentatively identified as Streptococcus agalactiae. One hundred 

 strains of staphylococci isolated from cows in the test herds are also be- 

 ing studied. 



The value of vaccines, chemicals, and segregation for the treatment 

 and control of mastitis is being studied. 



A new drug — Prontylin (powder form) — Prontysil (liquid form) — 

 has been used by Dr. Martin on several affected cows. The recommended 

 dosage for this disease was not known. A small amount was used over a 

 two-weeks' period, and no beneficial results were obtained. More 

 work will be done with this drug in connection with treating mastitis. 

 {Purnell Fund) 



Haemolytic Streptococci in Pasteurized Milk 



The studies on the haemolytic streptococci in pasteurized milk were 

 brought to a conclusion by L. W. Slanetz during the year. Sixty strains, 

 35 from pasteurized milk, 7 from utensils, and 2 from cow teats, have 

 been studied in detail and classified in five groups. The streptococci in 



