82 MASS. EXPERIMENT STATION BULLETIN 315 



310 Supplementary Mid-Morning Feeding of Rural School Children. Bernice 

 Wait, Oreana Merriam, and Madaline V. Cowing. 48 pp. illus. June, 1934. 



The effects of giving a mid-morning lunch to children have been studied in four rural 

 elementary schools which involved some 700 children. The lunches consisted of pasteurized 

 milk, reconstituted evaporated milk, tomato concentrate, and a mixture of evaporated 

 milk and tomato juice. There is included a full description of the methods used and the 

 difficulties encountered in trying to measure the effect of the various lunches on the condition 

 of the children. A definite though not marked improvement in the children seemed evident 

 with the feeding of milk, whether pasteurized or evaporated, or a mixture of milk and 

 tomato. Much less improvement was indicated with the feeding of the tomato concentrate, 

 though the difference would probably have been less had as much tomato as milk been 

 given. Improvement was noted in the children who were in good condition as well as in 

 those who were in fair or poor condition at the beginning of the study. 



311 Infectious Laryngotracheitis Vaccination. Charles S. Gibbs. 20 pp. illus. 

 July, 1934. 



The loss from infectious laryngotracheitis in poultry flocks in the State of Massachusetts 

 is a matter of much economic concern. An interest in the control of this disease has resulted 

 in field and laboratory experiments to develop a satisfactory method of producing immunity 

 through vaccination. This bulletin reports a method of preparing and using autogenous 

 vaccines which has proved satisfactory in both laboratory and field tests. It should be 

 understood that this method of vaccination will save the flock if properly applied, but can- 

 not be depended upon to eliminate carriers, and it should therefore be followed by complete 

 eradication and sanitary control of the disease. Vaccination for infectious laryngotracheitis 

 merely enables the poultryman to choose the time for disposing of the birds and cleaning 

 and disinfecting the premises occupied by them. When accepted in this light, vaccination 

 is a valuable contribution to the control of infectious laryngotracheitis. 



312 Effects of Inbreeding on Fecundity in Rhode Island Reds. F. A. Hays. 

 8 pp. October, 1934. 



Inbreeding has been used extensively for establishing uniformity in herds and flocks. 

 This report covers the results of inbreeding poultry for high fecundity characters when rigid 

 selection of female breeding stock was practiced. In no respect were the inbreds or inbreds 

 crossed found to be superior to the general flock. Apparently nothing is to be gained from 

 the standpoint of fecundity by inbreeding. 



313 Time Interval from First Egg to Standard Egg Weight in Rhode Island Red 

 Pullets. F. A. Hays. 12 pp. October, 1934. 



In breeding for egg size an important consideration is the time required by pullets to 

 attain 24-ounce egg weight. This report is concerned with a number of factors that vitally 

 influence this time interval. Analysis of the data showed that about 58 percent of the varia- 

 tion in time to standard egg weight was due to variation in the following: hatching date, 

 age at first egg, weight at first egg, winter clutch size, winter pause, broodiness, and persis- 

 tency; while the other 42 percent was probably due to unknown hereditary factors. In 

 breeding to increase egg size, it seems advisable to select breeding females exclusively from 

 those which attain standard egg weight in less than 75 days after the first pullet egg. 



314 Effect of Aging Treatment on the Bacterial Count of Ice Cream Mixes. 

 W. S. Mueller and R. L. France. 8 pp. October, 1934. 



This investigation was undertaken to determine whether the aging temperature of 6S°F., 

 considered desirable when gelatin is used in the manufacture of ice cream, has an unfavorable 

 effect on the bacterial count of the product. The following results were secured: 



The aging of pasteurized ice cream mixes for 6 hours at 08°F., whether followed by aging 

 for 18 hours at 38° or not, did not result in a significant increase in the number of bacteria 

 present; but similar aging of unpasteurized mixes did materially increase the number of 

 bacteria. When a pasteurized ice cream mix was aged for 24 hours at OS , a definite in- 

 crease in the bacterial count did not occur until after the tenth hour; and when held for 

 24 hours at 38°, no material increase occurred. 



Control Bulletins 



72 Seed Inspection. F. A. McLaughlin and Margaret E. Nagle. 47 pp. Feb- 

 ruary, 1934. 



