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II. THE LACTOMETER.

1. The lactometer is a hydrometer which indicates specific gravities between 1.000, the gravity of water, and 1.0348.

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oeg བྷཱུ g

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2. It is used to determine the specific gravity of the milk.

3. As the specific gravity varies with the temperature, the observations are made at a standard temperature of 60° Fah.

4. The specific gravity of the average milk at a milking of a healthy cow, properly fed and in a normal condition, varies from 1.029 to 1.0348. The former number being the lowest or minimum gravity, 100° is placed at this point on the lactometer; 0° is placed at 1.000, the gravity of water; the intervening space is divided into 100°, and the graduations are continued to 120°, which corresponds to the specific gravity 1.0348.

5. To apply the lactometer, the temperature of the milk is first noted with the aid of the thermometer; the lactometer is then carefully inserted, taking pains to avoid wetting the portion of the stem above the milk, and to free the surface of the milk from foam. The degree to which the instrument sinks is then noted. Bearing in mind the effect of temperature on the gravity, the inspector now decides whether the gravity will probably be below 100° at 60° Fah. If he thinks it will, he carefully cools or warms a sample of the milk, as the case may require, to 60° Fah., and again inserts the lactometer. If it stands below 100°, the gravity is below that of any genuine milk. He carefully notices the

The Lactometer.

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consistence to determine whether he has before him a sample of thin watered milk or a sample of thick cream. The black background of the shot in the lower bulb enables the inspector, as the milk runs off the lactometer, to judge of its consistence. The color is also noted, as well as the odor and taste. Low specific gravity (below 100° 1.029) together with abnormal watery consistence, and a watery taste, establish the fact of adulteration by water, which is the most common form of adulteration, because the simplest and most convenient.

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If the specific gravity be above 100°, it does not follow that the milk is pure and unadulterated. Skimming, by removing the lighter cream, increases the gravity of the milk; so skimmed milk is heavy; but it appears at the same time very thin, and the inspector's attention will be at once arrested by the inconsistency of high gravity and a watery character. In this, as in other cases where the inspector suspects adulteration of any kind which cannot be proved by the above-mentioned tests of gravity, consistence, and taste, he is instructed to take a sample for further examination by the cream test, chemical analysis, and the microscope,

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III. REPORT OF DOCTORS WALLER AND O'CONNOR ON THE COWS OF THE MULFORD FARM.

NOTE.-Samples of low gravity milk from this farm were introduced by the defence to prove that genuine, unadulterated milk, from healthy, well-fed cows sometimes shows a specific gravity below 1.029 (100° on the lactometer), the standard used by the Board of Health, and others, as the minimum gravity of pure milk.

W. DE F. DAY, M.D., Sanitary Superintendent.

SIR: We have the honor to report that, at the request of the President of the Board of Health, we visited the farm of Mr Charles Mulford, in the neighborhood of Guymard, Orange Co., N.Y., about 80 miles from New York. We reached there on the afternoon of Saturday, December 23d, 1876, and were present at the evening's milking.

His herd consists of some 22 cows, of which but four were at that time regular milkers; eight were "strippers," or cows that were nearly dried up, and the rest were dry. Only the regulamilkers were milked that evening.

Evening milking-" milkers;" milked twice a day:

The cow Charley was stated to be half Ayrshire; all the others were of the common breed.

That evening, after all had retired, Mr. T. C. Doremus and his friend, Mr. Root, arrived, and the next morning (Dec. 24th) the cows were milked in our presence, and the milk tested with the lactometer, both by the above-named gentlemen and by ourselves The results were as follows:

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Morning milking-"milkers;" milked twice daily.

With the exception of the Black cow, all of the strippers were with calf and were expected to be delivered in about 2 or 24 months. The Black cow had never yielded much milk since her calf was taken from her, and was to be fatted and killed for beef. Her milk looked very thin and watery, and was full of stringy curds which clogged the strainer. Indeed the product from all the strippers was not true milk, and was in no way suitable for domestic use. The product from the pregnant cows was essentially colostrum.

The total yield of the four regular milkers for the evening and morning together, was 34 quarts, an average of 8 quarts per day from each cow, which is considered a fair average yield for the winter season.