248 INFECTIOUS AND PARASITIC DISEASES. 



voided, or be passed off on the physician as having 

 been voided. Where the objects are really passed 

 in the urine, they are introduced into the urethra or 

 bladder before micturition. Hair, however, may be 

 passed in the urine in cases of dermoid cysts of the 

 bladder. 



When preparing a specimen for examina- 

 CoLLECTioN tion, a portion of the full twenty-four hours' 

 OF Specimen, secretion should be chosen. Although 



this does not always furnish the most 

 satisfactory sample, it is the safest rule to follow in the 

 absence of specific instructions. In one form of Bright's 

 disease, for example, albumin is present only an hour 

 or two after meals, and then in very small amounts, 

 so that the examination of a twenty-four hours' mixture 

 might not reveal its presence. In like manner, in 

 diseases of the genito-urinary organs, the twenty-four 

 hours' secretion does not give as much information as 

 one or several specimens collected during a single act 

 of micturition; and in affections of these parts the 

 patient is directed to divide his urine while voiding it 

 into two or three portions. If possible always send 

 at least four ounces of urine for examination. Unless 

 the urine can be examined in a few hours, keep it in a 

 cool place; or add to it gr. v of boracic acid, or one 

 dram of chloroform, to every four ounces of urine. 

 Formalin, m. i to four ounces, is also an excellent 

 preservative. 



