68 



Scientific Proceedings (27). 



the crystals belong to various systems. This indicates a common 

 substance in hemoglobin or a common structure in the various 

 hemoglobin molecules. 



5. The importance of twinning in the formation of crystal aggre- 

 gates and the constant recurrence of certain types of twinning in all 

 of the hemoglobins. These results will likely throw light upon the 

 mechanism of twinning and be of importance in general crystal- 

 lography. 



6. Differences between oxyhemoglobin and hemoglobin or re- 

 duced hemoglobin, in certain species. Undoubted differences between 

 the crystals of these two substances in the crystals of the same 

 species have been observed. 



We have gathered additional evidence leading to the conviction 

 that other corresponding proteins, as well as certain fats and car- 

 bohydrates, will be found to exhibit similar generic specificities. 



Our first memoir on this subject will shortly be published by 

 the Carnegie Institution of Washington, under whose auspices 

 this research is being conducted. 



38 (294) 

 The germicidal property of milk. 

 By M. J. ROSENAU and GEO. W. MCCOY. 



\_From the Hygienic Laboratory, U. S. Public Health and Marine 

 Hospital Service, Washington, D. C.~\ 

 Judged by the number of colonies that develop upon agar 

 plates the bacteria in milk first diminish, then increase in number. 

 The so-called germicidal property of milk occurs only in the fresh 

 raw fluid. 



For the most part our work plainly shows that no actual re- 

 duction in the number of bacteria occurs. However, when com- 

 pared with the controls a restraining action is evident. The phe- 

 nomenon, therefore, appears to be that of a weak antiseptic rather 

 than that of a true germicide. 



When milk is kept warm (37 0 C), the decrease is pronounced 

 within the first eight or ten hours. After this time the milk has 

 entirely lost its restraining action. 



When the milk is kept cool (1 5 0 C.) the decrease is less marked, 

 but more prolonged. 



