50 REPORT OF DEPARTMENT OF BACTERIOLOGY OF THE 
In order to determine accurately the inhibiting effect of chloro- 
form, the standard of comparison should be the action which 
takes place in the absence of the substance being tested. In 
the case of milk, this is not possible, since, unless there is suffi- 
cient chloroform present to repress the bacteria, they will promptly 
induce such profound changes as to obscure the action of the in- 
herent milk enzyms. This took place in the case of some of 
our bottles containing the lower percentages of chloroform where 
the bacteria were not repressed. The first experiment was de- 
signed to test the range from amounts which would not hold the 
bacteria in check up to 2.5 per ct., which was the percentage 
ordinarily used in our studies of the milk enzyms. 
In this experiment duplicate bottles of milk received 0.1, 0.2, 
0.3, 0.5, 0.7, 1.0. 1.5, 2.0. and 2.5 per ct. of chloroform, respectively. 
Each bottle contained 1 litre, the milk coming from our own herd 
and normally containing 5 per ct. of fat, but in this case the fat 
had been removed until only 0.015 per ct. remained. The bottles 
were held at approximately 15.5° C. (60° F.). The results of the 
chemical and bacterial examinations are given in Table X. 
TABLE X.— SOLUBLE NITROGEN IN CHLOROFORMED SKIM-MILK.* 
a ea eS I RE AS PS SN ST REESE SE TSR SPINS SEES SESE SSS SSSI TESEST IE TN SE a 


















PERCENTAGE OF CHLOROFORM. 
INTERVAL. 
OA. eur pA:2 0.3 0.5 0.7 1.0 1.5 2.0 | 2.5 
Soluable nitrogen e|xpressed jin percjentage | of total nitro|gen. 
Hindatsteblisteey: ware cn Bene te te 14.16} 14.16) 14.16] 14.16) 14.16) 14.16) 14.16) 14.16) 14.16 
WP castor fata UR el UE Raman eee Pera 35.55). 37.42) 37.750) 35.38) 31.50} 26152) 2ot4ble2or6e 
30..54|, 38.06) 36.14) 35.27| 33.69) 30.18) 25 Sijeesee7 
RITIOSLUeH Fe cs Enea ue ace 45.72| 45.53} 49.18! 49.10] 45.66] 39.96] 39.77] 35.60) 38.67 
44.73) 44.20) 48.98] 48.18) 46.74] 38.93) 35.49) 34.92) 34.02 
Gano sae ee aieibeues ae 41.70} 51.50) 50.58) 50.42) 50.64] 43.88) 39.96) 43.29] 35.07 
47.20} 48.26) 50.01] 48.35) 50.00] 43.48] 42.06!) 39.85) 40.23 
Bacteria per cubic }|centimet jer foun/d in thjese mil|ks. 
FG Gal aA OE wie Maca ay 162 sOO)Os >. cschadnae one’ frail ad add om Quad Sil otebaiecar ell oh eee es alien nea 
ATION GPa eee eke Curdled 48 38 36 30 533) 46 35 46 
44 3D 50 1D 25 43 44 42 
LTE S miu ive tet cats Too 33 30 39 25 12 26 ns 25 
many to 43 30 38 16 19 12 16 33 
count 
GitnOosmemt nam. . tive 188,700 18 18 12 14 oe 10 10 13 
14 34 14 6 8 4 12 " 






* Chemical determinations by Mr. Hart and bacteriological by Mr. Nicholson. 
- 
Since the first demonstrable effect of enzyms in milk is to 
bring nitrogen into solution, the percentage of nitrogen in this 
form has been used as a measure of enzym action. ; 
The bacteria were not held in check in the bottles containing 
0.1 per ct. of chloroform and this milk curdled at the end of 
_— 
