New York AGRICULTURAL EXPERIMENT STATION. 143 
We thus had (1) milk without any addition, (2) milk with 
sucrose alone added, (3) milk with yeast alone added and (4) 
milk with the same amount of yeast and. varying amounts of 
sucrose added. These were all kept at 100° F. for about three 
hours, as in the operation of preparing kumiss; they were shaken 
occasionally. The milk was then transferred to half-liter pres- 
sure bottles fitted with tight stoppers (Plate V, figs. 1 and 2, 
and Plate VI, fig. 4) and these were kept at a temperature of 
40°-45° F. during the continuation of the experiment. 
The contents of these bottles were-examined for acidity at the 
intervals indicated in Table I, one bottle being used for each 
examination. - In making the determinations, we used 50 cc. of 
milk, boiling the sample in order to expel carbon dioxide before 
titrating with = alkali. The results, expressed in percentages 
of lactic acid, are given in Table I. 
i 
TasLte I1— SHOWING AMOUNT oF AcID IN MILK AND KumiIss. 
| 










P= 
2 
5 
oy METHOD OF TREATING MILK.| Fresh.}1 day. 2 days. | 3 days. | 4 days. | 5 days. |6 days. 
o8 
ro} 
vi 
Per ct.| Per ct.| Perct. | Perct.| Perct.| Per ct. |Per ct. 
1 DRM is. 5 irae h Sivesatale so OF LF ORS TelrcOey Cgh ter Scents cle, ee ee Ctr ee Rhee cok 8 
2 MME CATS SUCTOSES iss] « sec Nhe tae CUO SOL AUP aates lus eek > [lode Seite ple 
3 WilliesPtveastt obi. . 80). £94 ORAS POO sH4 at COMES tls carci eek he sc 
4 ‘| Milk+yeast+5 grams su- 
Braectt ke. tek. LAs. Goats ORS2ie-O0. GOs pr ecOeSae ke ase sath eee te ees dA. 
4a | Milk+yeast+10 grams su- 
erueeits otter Moa), 028941 C0250 100. Date CU dels COSA leony oh. 
4b | Milk+yeast+20 grams su- 
“UNL Ete oe, he ene ee OLS) aO..27 | CON 2A 0O 52 sb eS. ic0 «86 
4c | Milk+yeast+40 grams su- 
BeOSeme Pil wt iets. 2% of bis 0.45 OVAL WOOD 27.4 BO). 321,60. 37a abO . 54 




— 
a Coagulated slightly on boiling but not sour. : 
b Coagulated quite completely on boiling but not tasting sour. 
c Coagulated almost completely without heating and sour. 
The results embodied in Table I are summarized in the following 
statements : 
(1) The untreated sample of milk was sour in two days. 
(2) The addition of sucrose alone to milk did not delay souring. 
(3) The addition of yeast alone apparently delayed the formation 
of acid slightly. 
(4) The addition of yeast and five grams of. sucrose did not 
reduce the acidity much below that of milk to which yeast alone 
was added. 
