dairyman agree that, were it possible for the cheesemaker to determine the casein. content of milk without involving too great an expense of time, and without introducing any large complication in computing values, then most assuredly we should pay for the milk according to both its fat and casein contents.

I intend to-day to describe and illustrate a very rapid and simple method. for determining the content of casein in milk which has been worked out in my laboratory, and under my direction.

The method, in short, consists in estimating by means of standard one-ninth normal alkali, in general use in our cheese factories, the acid liberated from casein by the action of the commercial solution of formaldehyde used so generally as a disinfectant and germicide.

It has been found by chemists that proteins, of which casein is an example, are very complex substances, compound for the most part of many, what we chemists call, amino-acids, combined in a very complex way. It has, further, been proved that these individual amino-acids contain both alkaline, or basic, groups, and acid groups, or parts. Further, when these substances are caused to combine with one another they do so in such a manner that some of the alkaline, or basic groups, and also some of the acid groups remain unaltered, with the result that the product is usually, if I may use the expression, both alkaline and acid, or, in other words, neutral. However, if we treat such a substance, which we shall call a protein, with formaldehyde we find that the formaldehyde undergoes chemical combination with the alkaline or basic part of the protein molecule, thus destroying or "fixing" its alkaline function, but leaving the acid part of the molecule free to act, with the result that we get a strongly acid reaction toward indicators. If we now titrate this acidity with a standard alkali we have a means of determining the amount of protein present. Of course we must know the "protein value" of the alkali. This "protein value" in the case of milk casein has been determined in my laboratory. We determined this in the following manner.

We determined the amount of casein by the chemical method in a large number of samples of milk, using ten cubic centimetres at a test. At the same time we found the amount of one ninth normal alkali necessary to neutralize the acid liberated from the casein by formaldehyde in ten cubic centimetre samples of the same milks. We then estimated the average ratio existing between the amounts of casein present and the amounts of alkali used, and expressed this ratio in percentage of casein. The result was that with 10 c.c. samples of milk, 1.63 c.c. of alkali corresponded to one per cent. of casein. That is to say, for each 1.63 c.c. of alkali used we found one per cent. of casein present in the milk of a ten c.c. sample. In order, then, to determine the percentage of casein present in an unknown sample of milk, one uses a ten c.c. sample and multiplies the number of cubic centimetres of alkali used by 1.63.

In order to simplify the calculation we now use a 16.3 c.c. pipette to take the sample of milk, and read off directly on the burette containing the alkali the percentage of casein, that is to say, the number of cubic centimetres of alkali used, in this case, represents the percentage of casein in the milk.

The method consists, then, in taking a 16.3 c.c. sample of the milk and placing it in the test cup. The existing acid of the milk is now neutralized by adding the alkali exactly as in the case of the "acid test," after having first added the indicator. We use 1 c.c. of the indicator (1: 500). We also advise bringing the color to a good deep pink. We next add an excess of commercial formaldehyde solution, which has been rendered neutral with alkali, using, of course, a few drops of

indicator to show the neutral point. We advise using about 2 c.c. of the formaldehyde solution. The pink color of the milk now disappears at once since the acid of the casein has been set free, or rather, since the basic function of the casein has been fixed or bound. We now add the alkali again until we get the same shade of color as we had before we added the formaldehyde. The amount of alkali used in this last titration represents the percentage of casein in the milk. This is obtained, of course, by subtracting the first reading on the burette from the second reading. To eliminate the trouble of this subtraction, I have devised a new form of acidimeter, which you now see, which is a so-called automatic zero point acidimeter, by means of which the alkali is brought to the zero point in a moment after the first titration, and thus the trouble of subtraction is eliminated. This acidimeter will be placed on the market in a short time, when it will be available, not only as a casein test, but as a general acidimeter for the acid test.

The time required for the complete test of course varies with the skill of the operator, but should not occupy more than two minutes. Further, when a large number of tests are made consecutively, the time may be cut down appreciably by taking a number of samples in succession, without laying down and taking up again the pipette between each sample.

The test makes use of only those substances in common use in cheese factories, namely, the standard alkali, the ordinary indicator, and the pipette and acidimeter, with the exception of the formaldehyde, which is a very cheap substance and readily obtained at any drug store.

It is, further, no more difficult to carry out than the ordinary acid test, and therefore can be operated by any cheesemaker.

At the time the details of the test were worked out some months ago, no preservative was in common use which permitted its use with composite preserved samples. During the last few weeks I have been carrying on a series of experiments to discover a preservative which will preserve milk for a month, and will not interfere with either the test for fat, or the casein test. As yet the experiments are not complete, but I have hopes of obtaining satisfactory results in the near future.

MR. BARR: Does the temperature make any difference to the test?

PROF. WALKER: No, we will get exactly the same result one day as another and the test does not vary with conditions. It will give you the same result whether it is 40 or 50 degrees or 90 degrees; it is a chemical test.

SENATOR DERBYSHIRE: Do you know anything about Mr. McLaren's arrange

ment?

PROF. WALKER: No.

SENATOR DERBYSHIRE: He can put a bottle of milk in his pocket and keep it there for two years and then drink it by the wayside. There is no trouble about it; I have seen the milk. He pulled a bottle out of his pocket in Winnipeg and gave me a drink.

PROF. WALKER: There is very little literature on milk preservatives. I hope to be able to make a preservative that will keep milk for a month.

THE NEW EXPERIMENTAL DAIRY STATIONS.

G. H. BARR, CHIEF OF THE DAIRY DIVISION, OTTAWA.

In Eastern Ontario there are many sections in which the factories are small and poorly equipped, and the dairy division spent some time looking over the situation before selecting a location to build a dairy station. At Finch the conditions seemed favorable for several reasons. The railway connections were convenient to Ottawa; the district was a fairly good dairy section and could be improved very greatly; the cheese in the district were not noted for their fine quality and there might be an opportunity to assist in improving this condition; there were two small factories close to the village which were cutting each other's throats,

to use a common expression. We purchased these and by uniting them in our dairy station, we feel we have done the right thing, and we hope that we will be able to assist in overcoming some of the other weak features in the district. Although we have only been located at Finch one season, I know that there are already some improvements in the district which I do not believe would have taken place had we not come there.

This subject is probably not as interesting as many others that have been discussed at this Convention, but we may grow crops, keep cows, feed them well and take care of the milk and cream in the very best way at the farm, yet to get the very best returns, we must have a proper place in which to manufacture that milk and cream into cheese and butter.

In erecting these dairy stations, the dairy division had two objects in view: first, we wished to secure a suitable place in which to carry on experimental work and, second, the buildings would serve as models for those wishing to build new cheese factories or creameries. There is nothing elaborate about these buildings. They are simply good substantial buildings in which the work can be done conveniently and well. The same may be said about the equipment.

I will try briefly to point out a few features about these dairy stations which I think may interest you. One of the worst features of the cheese business in Eastern Ontario is the small and poorly equipped factories. We made an effort to overcome this at Finch by purchasing two small factories located near the village

and uniting them in our dairy station, and in this new building we hope to give the patrons better service than they ever had before.

The factory is built of hollow cement blocks. We used this material, because we thought it the cheapest in that section. Personally, I like either a brick or frame building better than one built of cement blocks; still the Finch building looks very well. The foundation of the building is concrete, four feet deep, eighteen inches wide at the bottom and tapers to nine inches wide at the top with the slant on the outside. This makes a splendid foundation and I would much rather build it in that way than have it the same width all the way down. The specifications for the concrete mixture were as follows:

The concrete for the foundations shall be composed of one part approved Canadian Portland cement and four parts clean, sharp sand mixed dry, then moistened with a minimum quantity of water and incorporated with four parts of coarse gravel or 2-inch broken stone.

The cement blocks are rock faced, two feet long, eight inches wide and nine inches high.

In the making room, creamery, office and engine room, there is no inside. finish on the walls. We intend to paint or whiten the cement blocks.

The specifications for insulating the ice chamber, curing room and refrigerator were as follows:

OUTSIDE WALLS OF ICE CHAMBER and RefrigeratoR.-Erect against cement block 2 x 1 inch furring strips at 2 feet centres and cover with one course of 7-8 inch T & G sheathing. Over this lay two ply of damp proof paper to be held in place with thin strips or lath. Erect 2 x 6 studs at 2 feet centres placed to bring the inside edge one foot from surface of sheathing already erected leaving a space of 12 inches to be filled with shavings. Cover with one course of 7-8 inch T & G sheating, two ply of damp proof paper and finish with 7-8 inch T & G spruce sheathing free from shakes, large or loose knots. Space between studs to be filled. with dry planer shavings.

OUTSIDE WALLS OF CURING ROOM.-Lay over inside surface of cement blocks, two ply of damp proof paper held in place by thin strips or lath. Set up 2 x 4 inch studs, 24 inch centres, with inside edge 8 inches from inside surface of wall, so as to leave a space of 8 inches between wall and sheathing. Lay one course of 7-8 inch T & G sheathing, two ply of sulphite building paper and finish with 7-8 inch T&G spruce sheathing, free from shakes, large or loose knots. Space between wall and sheathing to be filled with dry planer shavings.

PARTITION BETWEEN ICE CHAMBER AND CURING ROOM.-Erect 2 x 4 inch staggered studding at 24 inch centres, leaving a space of 12 inches between the outside face of each row of studs. (See detail.) (See detail.) On the side next the ice chamber, lay one course of 7/8 inch T & G sheathing, 2 ply of damp proof paper ("Neponset" or "Hercules") and finish with one course of % T & G spruce sheathing free from shakes or large or loose knots.

The side next the curing room to be finished in a like manner, except that sulphite building paper may be substituted for damp proof paper.

PARTITION BETWEEN CURING ROOM AND DRYING ROOM.-To be erected in the same manner as partition between curing room and ice chamber, except that sulphite building paper may be used on both sides. In every case, two layers of paper well lapped must be used.

CEILING OF ICE CHAMBER.--Lay 2 x 10 inch joists on top of walls at 30 inch centres. On the under side, cover with one course of 7% inch T & G sheathing, two ply of damp proof paper and finish with 7/8 inch T & G spruce sheathing. The space between the joists to be filled with dry planer shavings. Lay one course of % inch T & G sheathing on top of joists. Make a hatch 4 feet x 3 feet in ceiling of ice chamber where directed and fit same with double doors.

CEILING OF REFRIGERATOR.-Lay 2 x 8 inch joists on tip of wall at 30 inch centres. On under side cover with one course of 7/8 inch T & G sheathing, two ply of sulphite paper and finish with 7% inch T & G spruce sheathing, the space between the joists to be filled with planer mill shavings to a depth of 14 inches.

CEILING OF CURING ROOM.-Place 2 x 8 inch joists 21 inch centres with lower edge 9 feet in the clear above floor. Provide and erect the necessary beams to