38 METHODS OF OBTAINING HUMAN AND ANIMAL BLOOD 



physical condition. Kaplan has cautioned against making lumbar 

 puncture in the presence of tumors of the posterior fossa, particularly 

 of the cerebellum. When it is highly desirable to study the fluid of 

 such cases, 2 c.c. may be withdrawn, and immediately replaced with 

 sterile normal salt solution, or if no immediate effects are observed, the 

 patient may be kept in bed for the next twenty-four hours. 



Preparation of Patient. In bed-fast patients the puncture may be 



FIG. 17. A WET CUP FOR SECURING BLOOD FROM CHILDREN. (Devised by 



Blackfan.) 



The cup is held in this position over a scarified area; air is exhausted by means of 

 a pump attached to the rubber tubing; blood collects in the small test-tube. 



made at any time; with ambulatory patients, however, the most suit- 

 able time is late in the afternoon, so as to permit the patient to rest over- 

 night. 



The ordinary preparations consist in scrubbing the skin of the lumbar 

 region with green soap and hot water, using gauze sponges, followed by 

 washing with alcohol and ether. The area is then covered with sterile 

 gauze, and, just before the puncture is made, an application of 10 per 

 cent, tincture of iodin is made; or the preliminary cleansing may be 



