55 



Taking the Sample. 



The time when a sample of milk is taken is by no means un- 

 important, and, in the case of woman's milk, presents some diiB- 

 culties. Ilerbivora give their milk generally at stated periods ; in 

 the case of woman, however, it is different, and the taking of the 

 sample is more difficult. With the report on an exact analysis, 

 such data, giving the' details with regard to the sampling, are in- 

 dispensable. 



Conrad proposes that the sampling be done, if possible, by the 

 analyst himself, to prevent intentional or unintentional delusion. 

 The best time for this is from two to three hours after the last 

 nursing, when the breasts have filled again, and are ready for 

 another nursing. The whole of the milk is then drawn, either by 

 means of a breast pump, or by the use of forefinger and thumb, 

 when it is collected in a clean, dry beaker. This latter manipula- 

 tion can, with some practice, be conducted without causing the 

 least pain, and is preferable to the use of the breast pump, since it 

 brings the milk quicker, and because it famishes better indications 

 regarding the quantity of milk, and also its quality and consis- 

 tency. By observing if the milk flows in thicker or thinner strains, 

 valuable hints regarding the explanation of certain irregularities 

 with reference to the nursing of the infant, and its digestion, may 

 be obtained. 



Thus, from 30 to 50 or 100, and sometimes even 200 c.c, of 

 milk may be obtained. For really exact investigations, the milk 

 from both breasts should be drawn and intimately mixed before 

 the examination. 



Physical Examination. 



The specific gravity is determined for scientific purposes by 

 means of a bottle of known weight and contents. For ordinary 

 purposes, a lactodensimeter of Quevenne, of reduced size, may be 

 used (Conrad's). They allow the determination of the specific grav- 

 ity in from 30 to 40 c.c. of milk. The manipulation and calcula- 

 tion are the same as will later be mentioned in the chapter treating 

 on " Milk inspection." For a better estimation of the quality of 

 woman's milk, a determination of the fat by means of the lacto- 

 butyrometer should be made. 



