26 MASS. EXPERIMENT STATION BULLETIN 347 



Value of Pedigree and Certain Parts Thereof in Predicting Production of Bull's Daughters 



Percentage of 

 Percentage Bulls Whose Correlation Between 



With Less Daughters Indicated Method at 



Range of Than Exceeded Average Left and Bull's 



Material Errors 5% Error Expectations Error Daughters Average 



Guernsey Pedigree Index —16 to +14 80 70 4 40 =.62+.07 



Jersey Pedigree Index 



(Uncorrected) -52 to +18 20 20 15 79 =.19 ±.11 



Jersey Pedigree Index 



(Corrected) -41 to +13 37 20 12.06 =.41 ±.09 



Jersey Sires' Daus. 



(Uncorrected) -40 to +14 20 20 16 01 =45+. 09 



Jersey Sires' Daus. 



(Corrected) -31 to +14 26 20 12 00 =.54± .08 



Jersey Dams' Record. .. -101 to +28 11 11 27.40 =.18±.ll 



Jersey Dams' Record 

 Averaged with Sire's 

 Daughters Average ... . -55 to +16 28 20 1594 =.28 +.10 



Jersey Sire's Dau. Aver- 

 age and Dam's Rec- 

 ord (Uncorrected) ... . -67 to +6 9 9 20.34 =.33 ±.10 



Jersey Sire's Dau. .Aver- 

 age and Dam's Record 

 (Corrected) Averaged 

 with Sire's Daughters' 

 Average -43 to +11 26 17 13 70 =.47±.09 



Jersey 3 Nearent Sires 



(Uncorrected) -43 to +20 31 28 13.43 =24+. 10 



Jersey 3 Nearest Sires 



(Corrected) -52 to +10 37 26 10.98 =46 ±09 



Jersey 5 Nearest Sires 



(Uncorrected) -41 to +26 31 37 11.70 =.15±.ll 



Jersey 5 Nearest Sires 



(Corrected) -31 to +15 30 50 9.80 =43+. 09 



DEPARTMENT OF BACTERIOLOGY 

 Leon A. Bradley in Charge 



The major part of the research program in bacteriology for this and several 

 preceding years has been the study of the physiology of bacteria of the Coli- 

 Aerogenes group. The Standard Methods of Water Analysis of the American 

 Public Health Association employs the group as an indicator of the sanitary- 

 quality of a water supply. It must be pointed out, however, that the Standard 

 Methods procedure is designed primarily to test filtered and treated municipal 

 water supplies. Experience in this laboratory has been that the standard is too 

 rigorous for the wells and springs that supply farms and rural homes. Certain 

 authorities on water bacteriology maintain that, of the Coli-Aerogenes group, 

 only Escherichia coli and perhaps closely related intermediates of the group are 

 certain indicators of sewage pollution; and that Aerobacter aerogenes and closely 

 related intermediates indicate only surface drainage, and if they indicate sewage 

 pollution at all, it is so remote in time as to be harmless. 



This laboratory is frequently faced with the necessity of deciding upon the 

 quality of a water sample which would be condemned on the basis of the bacterio- 

 logical test, but not on the basis of available information concerning the location, 

 construction, and surroundings of the well or spring in question. The condemna- 



