1903.] 



Role of the, Blood Fluids in Phagocytosis. 



361 



Different results, however, emerge when experiments in duplicate 

 are conducted with tubes presenting extreme differences in calibre. 

 In a series of comparative experiments, in which we employed in each 

 case an almost hair-fine capillary tube as a fellow to a tube 

 almost too large to be reckoned as a capillary tube, the results 

 were irregular, being generally but not consistently in favour of the 

 narrower tube. 



A second point which comes up for consideration is the possible effect 

 of the addition of citrate of soda to the blood. 



The concentration of the solution in particular comes into considera- 

 tion. Finding that phagocytosis is inhibited when the white corpuscles 

 are bathed in a medium containing 3 per cent, of citrate of soda, we 

 took the precaution to add to the blood in comparative experiments 

 precisely the same amounts of citrate of soda. It may be noted that 

 the morphological structure of the white corpuscles is extremely well 

 preserved, and phagocytosis proceeds actively in a medium containing 

 up to 1*5 per cent, of citrate of soda. 



The third and last point to be considered relates to the maintenance 

 of the activity of the phagocytes for a sufficient period after they have 

 been withdrawn from the organism and have been subjected to the 

 procedures described above. It will be manifest that, apart from a 

 maintenance of the activity of the phagocytes under the conditions 

 which come into consideration here, it would be impracticable to 

 compare the results of experiments instituted in succession with one 

 and the same quantum of washed corpuscles, or to compare the phago- 

 cytic power of different bloods unless in the case where these were 

 withdrawn from the organism simultaneously. 



A number of experiments undertaken with a view of obtaining 

 information with regard to the point here raised have shown us that 

 the phagocytic power is well maintained under the circumstances of 

 our experiments. Even after the lapse of 3 days (our observations 

 have not extended beyond this limit) the phagocytic power has not 

 declined to less than one-half or one-third of that of the blood freshly 

 drawn. We have found no indication of a variation within the space 

 of a few hours. 



These preliminary points having been dealt with, we may pass to the 

 consideration of the problem to which attention was directed in the 

 opening paragraph of this paper. 



