152 POWDERED VEGETABLE DRUGS 



Imitation smoking opiums composed of syrups, vegetable jams and 

 jellies, etc., are offered for sale by opium smugglers. This double 

 crime and deception is readily detected by means of the compound 

 microscope. 



7. Determining the Fat Content of Milk and Cream by Means of the 

 Compound Microscope. By means of a pipette graduated into tenths 

 of 1 cc., run 0.5 cc. of the thoroughly mixed sample of milk into a 100 

 cc. graduated cylinder and add warm (not hot) distilled water up to the 

 100 cc. mark making a dilution of 1-200. Mix thoroughly by shaking 

 vigorously for 20 seconds. Warm the mixture in the sun or in the 

 incubator (at 37C.) for a few minutes and again shake. 



By means of a rather slender glass rod dipped well into the cylinder, 

 take up a droplet of the diluted well mixed milk suspension and place 

 on the counting chamber of the Thoma-Zeiss hemacytometer, cover 

 with cover glass, and make the counts of the butter fat globules, 

 following the suggestions already given under examination of starch 

 and flour suspensions. The Mooo cmm. areas are to be used in making 

 the counts and the average of not less than fifty areas counted (from 

 not less than two different hemacytometer mounts) is to be used as 

 the factor for estimating the fat content of the milk under examination. 

 578,100,000 butter fat globules per cc. of milk corresponds to 1 per 

 cent, of butter fat. Dividing the number of globules found in the 

 sample under examination by 578,100,000 will give the percentage 

 of butter fat present. 



Caution must be observed in making fat counts of pasteurized and 

 boiled milks as many of the globules are more or less agglutinated. 

 The method is not recommended for evaporated and condensed milks 

 (sweetened and unsweetened), although the tests thus far made would 

 indicate that the results are fairly reliable. For making fat counts 

 of cream use dilutions of 1-800 to 1-1000. 



8. Agar in Jams, Jellies and Similar Fruit Products. The usual 

 method is to ash a sample of the jam or jelly at as low a temperature 

 as possible, and to add weak hydrochloric acid for the purpose of 

 decomposing the carbonates, etc. In the presence of agar, the siliceous 

 skeletons of marine diatoms will appear in the ash residue when ex- 

 amined under the compound microscope. The following substitute 

 method is recommended : 



Dissolve as completely as possible (with heat) 5 cc. or 5 grams of the 

 substance in 100 cc. of distilled water and centrifugalize for 30 minutes 

 while still hot. Decant off all of the liquid (with suspended insoluble, 

 matter) excepting about 2 or 3 cc. of bottom sediments and examine 

 this residue under the compound microscope. In the presence of agar 



