G46 H. M. WOODCOCK. 



f,'reatest service to me, I have developed and extended 

 Novj and McNeal's method, m.iking use of it not only on the 

 dead bird, but also — what is much more difficult — on the 

 living bird. In taking drops of blood for culture-tubes, the 

 great desideratum is to get the region of the arm above- 

 mentioned sterile if possible. The part is very well washed 

 and gently rubbed first of all with cotton-wool soaked in 

 lysol, particular attention being paid to the skin near the 

 base of the feathers. The lysol must then be washed away 

 with distilled water, which has been well boiled. Lastly, the 

 water is absorbed as well as possible with more cotton-wool, 

 which has been boiled along with the water, and from which 

 the hot water is quickly pressed out. This is preferable to 

 using loose wool and serves to take up most of the water, 

 the warmth also helping in drying the part. It is most 

 important to have the arm as dry as possible before pricking 

 the vein, otherwise the blood spreads and runs over the 

 surface. As it exudes, the blood is taken up by a sterilised 

 Pasteur pipette, the drawn-out tube of which is long enough 

 to pass into the expression-water of the culture-tube. 



It is, of course, a much easier matter to get sterile inocula- 

 tions from the bone-marrow, heart, etc., if the ordinary 

 precautions are adopted. 



If a culture-tube can be successfully inoculated with four 

 or five drops of blood, I have found that in a few days 

 (usually five to seven, sometimes fewer) one can generally say 

 with confidence whether the bird was infected, according as 

 the tube develops trypanosomes or not. Unfortunately, even 

 with the greatest care, the inoculated tubes are sometimes 

 badly contaminated before tliat time has elapsed. In such 

 circumstances I never rely upon a negative indication, 

 though I may add that now and again a positive result has 

 been obtained where the medium had become contaminated. 

 When I have been unable to get any cultures to develop in 

 two or three sterile tubes taken from a bird, subsequent 

 examination and culture of the bone-marrow after death 

 have also proved negative. Hence I have regarded the 



