OBTAINING SMALL AMOUNTS OF ANIMAL BLOOD 41 



After-treatment of the Patient. Occasionally the needle may strike a 

 nerve filament, which occurrence is followed by more or less pain along 

 the course of its distribution; puncture of the bone is likely to be foK 

 lowed by pain for several hours. The majority of patients are so little 

 affected by lumbar puncture that no precautions as regards the after- 

 treatment are necessary. As previously stated, it is advisable for the 

 patient to rest overnight. Sudden release of pressure or the nervous 

 shock may give rise to severe headache of one or of several days' dura- 

 tion; persons of hysteric temperament may, in addition, suffer from 

 diarrhea and vomiting. Rest in bed, the application of ice-bags, and 

 the administration of sedatives are usually sufficient to relieve these 

 after effects. 



Disposal of the Fluid. As a general rule, the fluid should be sent 

 at once to a laboratory, as total cell counts and bacteriologic cultures 

 are best made with fresh fluid. For the Wassermann reaction it is not 

 advisable or necessary to add a preservative, as the fluid will keep for 

 several days in a good refrigerator; if, however, the fluid is to be kept 

 for longer periods of time, 0.1 c.c. of a 1 per cent, solution of phenol 

 may be added to each cubic centimeter of fluid. 



OBTAINING SMALL AMOUNTS OF ANIMAL BLOOD 

 Rabbit. 1. Flip an ear vigorously with the hand, and rub with 

 xylol and alcohol. The xylol produces marked congestion and after- 

 ward should be carefully removed with alcohol and water, as it pro- 

 duces a low-grade inflammatory reaction. 



2. Puncture a marginal vein with a large needle. The blood will 

 flow quickly in drops and practically any amount up to 10 c.c. or even 

 more may be collected in a centrifuge or test-tube (Fig. 19). For 

 making preliminary tests of serum during immunization 2 c.c. of blood 

 is usually sufficient. Bleeding may be checked by making firm pres- 

 sure over the puncture. 



Guinea-pig. 1. Blood may readily be removed directly from the 

 heart by anesthetizing the animal with ether, and inserting a sterile 

 needle into the heart at the point of maximum pulsation. A syringe 

 for aspiration may be attached, but better results are secured by ad- 

 justing a suction apparatus. By means of a short piece of rubber tub- 

 ing the needle may be connected to a test-tube so arranged that a 

 partial vacuum is created by attaching to a water suction pump. As 

 soon as the heart has been entered, blood is seen to flow into the tube 



