82 Report oF DEPARTMENT OF BACTERIOLOGY OF THE 
It will be remembered that it was the observed introduction of 
iron rust and other foreign material in this way that originally 
led to the adoption of the filter at this point. 
If the variations in the germ content on the two sides of 
the pail noted in the previous table were really due to the 
inefficiency of the cotton filter to successfully handle this sud- 
den inrush of air these variations in the germ content of the 
milk of the two sides of the pail should disappear if the air 
for destroying the vacuum was introduced from some other 
source. Accordingly the test with and without the presence 
of the cotton in the filter was repeated in the same manner 
as before except that in this experiment at the close of the 
milking after the stanchion cock was closed the air was allowed 
to enter gently through the teat cups. 
The results of these observations on four cows and using two 
milking machines are given in Table VI. 
TABLE VI.— GERM CONTENT WITH B-L—K MACHINES WHEN VACUUM WAS 
BROKEN THROUGH THE TEAT CUPS. 














Without cotton filters. With cotton filters. 
Machine © Machine Machine Machine 
No. 1287. No. 1288. No. 1287 No. 1288. 
Filter | Other | Filter |.Other Filter | Other | Filter | Other 
side. | side. | side. | side. side. | .side. | side. | side. 
Germs per cc. in milk, ’ Germs per cc. in milk. 
June 19.....}26,010]77 , 500/19, 850)18,098/|June 7.....| 3,710) 8,360/15, 510/13, 950 
Sa eZO SAE EE 5,280} 2,530/19,810/19,000 LOS ae 1,830} 3,820} 6,830] 3,300 
ce ner nhc ests 35, 250/32 ,850/17, 100)18, 500 o> oe /Lt hes 2,960] 1,250] 2,320) 2,440 
“» 22...+.|52,150} 9,170] 7,530) 8,990 be be KL Dike eer 2,970} 1,680} 1,720} 4,620 
~ 4 24.0, .{10,210) 5,270) 9240/12, 900 phn eT Sit hea. 3,850] 2,240] 4,860) 3,600 
25.05 16,000) 4,410] (45310) 49, 680i.“ “282.2 .8 (4,640; {680)*..... Ye mes 
M27 a 52h 8, 7601 15 360127, S70 aa Sao. BOW ee 16,160} 6,950}16, 230) 10,860 
July 2....111,190/44,330/16,050)18,230)|July 1..... 7,880} 2,750)10,660/14,350 
ng oe ao Le hake POT Ae TEL 5 eeCere Be iid ee x 3... .0| 5,760) 1,380) 6,190) °7,. 790 
Average... .|21,358|22,177|12,670|16,040 5 7528) 3,234 dao low OLs 
Gen. Av ..': 10,758 ee Wa" 4,383 7,764 

* Teat cups dropped; colonies overran the plates. 
