154 STATE BOARD OF AGRICULTURE. 



Otlier problems have been taken up, concerning largely the technic and 

 tlie reliability of methods in common practice. An extensive statement 

 of the attitude of this laboratory towards soil bacteriology is given in 

 the 13th Report of the Michigan Academy of Science, 1911." 



DAIRY BACTERIOLOGY. 



Mr. Charles W. Brown, Miss Zae Northmp, and Miss Lulu M. Smith 

 have been occupied with dairy problems during the past year. A brief 

 review of the dairy work conducted by Mr. Charles W. Brown and 

 Missi Lulu M. Smith is added: 



^'Butter InmsUgations. — An experiment with the keeping qualities 

 of storage butter that was begun almost two years ago ha.s been carried 

 along during the past year by Mr. C. W. Brown and Miss Lulu M. 

 Smith. It comprises a great amount of work dealing with pasteuriza- 

 tion and ripening compared with non-pasteurization and non-ripening as 

 factors in lessening the deterioration of storage butter. As this work 

 is now almost complete and as it is to be put out in bulletin form within 

 a short time, a mere mention of it here is deemed sufScient. 



Work with Yeasts and Torulae Found in Milk and Butter. — It wa.s 

 noticed that some of the yeasts and toralae isolated during our work 

 with milk and butter have the power of changing the acidity of milk. 

 And as the acidity of butter is associated with and related directly 

 or indirectly to rancidity, physiological investigations along the line of 

 acid production and acid consumption in the metabolism of these yea.sts 

 and torulae was thought necessary for a better understanding of some 

 of the changes that occur in storage butter. These investigations con- 

 ducted by Miss Smith are under way. 



Worl: with Bacterium Lactis Acidi. — A certain amount of work has 

 been done with various strains of Bact. lactis acidi with the idea in 

 view of obtaining information valuable to crearaerymen, cheeseraakers 

 and others who have 1o do with the carrying along of starters, the 

 ripening of milk and cream and the preparation of milk and whey cul- 

 tures for dietetic or medical purposes. 



Trouhles luith Off-Flavors in Milk and Cream. — At different places in 

 the state there has been trouble with oif-flavors developing in milk and 

 cream. It seems that these off-flavors make themselves evident during 

 the winter and are not noticed during the summer weather. Some at- 

 tention has been given to these troubles; and in one case there was 

 found in the cream, also in the well water and dust of the barn, a bacillus 

 that, if cultivated in cream at 15° C. or below produces the character- 

 istic olf-lhivor causing trouble. Precaution was taken to prevent the 

 troublesome organism from entering the cream with the result that 

 the trouble abated, but was not overcome com])letely." — [C. W. Brown.] 



Miss Zae Northrup submits the results of her work upon *'The In- 

 fluence of the Products of Lactic Oi'gauisms upon li<i<iUus Tifphosus'' 

 j>rinled elsewhere in this i-eport as Technical BuUelin No. 10. Miss 

 Northrup is also carrying on some experiments in connection with Dr. 

 G. A. Waterman. The purpose of this work is to secure a better under- 

 standing of the ]>roduction of pure milk. Miss Northnip adds the fol- 

 lowing concerning this work : 



"Dr. G. A. Waterman, former head of our Veterinary Department 



