262 Bulletin 38. 



nient to cool the milk for testing by allowing the test bottles, 

 into which the samples have been measured, to stand over night 

 and then test in the morning. If you do not have ice, wrap 

 a damp cloth about the bottles at night and they will be cool 

 enough when morning comes. 



4. Pouring acid into the test bottles. Hold the bottle in a 

 slanting position so that the acid will run down the side and not 

 through the milk. 



5. Addi?ig hot water. The water should be hot, too hot to 

 bear the hand in it. Soft water is to be preferred where it is avail- 

 able. 



6. Measuring the fat. The fat must be in a liquid condition 

 when the readings are made, and the measurement be from the 

 very top to the bottom of the column of fat. 



7. Speed of the machine. A machine ten inches in diameter 

 ( from the bottom of one bottle packet to the bottom of the opposite 

 one) should be given 1075 revolutions per minute; a fourteen-inch 

 machine 910 revolutions. Count the number of the revolutions of 

 the bottles to one of the crank and thus determine the rate of 

 turning for yourself. 



While the operation of testing milk by the use of the Babcock 

 test is simple, care must be exercised in its use ; inaccurate results 

 will surely follow careless work. 



Gordon H. True, 



Department of Animal Husbandry 



PLANT-LICE. 



No. 25, January i. 



Plant-lice (Aphididce of entomologists) are soft-bodied insects 

 of small size, which suck the sap of plants by means of a long 

 beak, the tip of which is thrust into the tissue of the plant. They 

 are allied to the scale-insects (Coccida) and are especially abund- 

 ant in temperate regions, the scale insects taking their place to a 

 great extent in the tropics. In the cooler parts of North America, 

 plant-lice are exceedingly numerous and destructive, but as we go 

 south they are less noticed, although some kinds affect even the 



