96 IOWA ACADEMY OF SCIENCES. 



Some experiments were also made in filtering germs out with the following 

 results: 



Water from veterinary hospital filtered through two, three and five thicknesses 

 of filter paper, funnel, flasks and filter paper previously sterilized: 



Unfiltered. Filtered. 



Two filter papers 250 germs per c. c. 129 germs per c. c. 



Three filter papers 250 germs per c. c. 24 germs per c. c. 



Five filter papers 250 germs per c. c. 4 germs per c. c. 



('ollege water supply from main building filtered through a Pasteur-Chamberland 

 filter after sterilization : 



Unfiltered. Filtered. 



Fifty germs per c. c. Sample No. 1, 4 germs per c. c. 



Sample No. 2. none. 



Water supply of North Hall standing in tank partially open, filtered through 

 sterilized asbestos: 



Unfiltered. Filtered. 



Six hundred and fifty germs per c. c. 4 germs per c. c. 



October 11th. Water taken from farm barn and filtered through sterilized glass 

 wool. 



Unfiltered. Filtered. 



Four hundred and eighty germs per c. c. Sample No. 1, 120 germs per c. c. 



Sample No. 2, 100 germs per c. c. 



These results show that so far as studying the Bacillus of Typhoid Fever, 

 samples should be collected on the spot; examinations and cultures should be 

 made immediately. A good many species were obtained, but none of these could 

 be identified with the Bacillus 1i;phi-abclominalis. Nor were any pathogenic 

 germs present. Water kept in a cool place showed that in the course of several 

 months, there was considerable diminution in the number of germs, but the 

 number was still large for potable purposes. Water can be advantageously filtered 

 by the Pasteur-Chamberland filter, ordinary glass wool; asbestos, and filter papers 

 also remove many of the germs. 



BACTERIOLOGICAL STUDY OP MILK AND ITS RELATION TO PUBLIC HYGIENE. 



We present here also a very brief report of the woik done by Mr. B. F. White 

 on the above topic. By ordinary methods it is an extremely difficult matter to get 

 milk from cows without germs. This, however, was accomplished quite easily by 

 using sterilized milking tubes. The number of germs was determined by taking 

 .25 c. c. of milk and pouring it in a known quantity of agar, making three dilu- 

 tions. Each tube was poured out on sterilized glass plates and allowed to stand 

 from 48 to 72 hours. They were then counted and some of the species cultivated 

 in the usual media. 



