On the Role of the Blood Fluids in Intracellular Digestion. 335 



Precision, capacity for truly quantitative measurements, uniformity of 

 adjustment and rapid working, are among the most urgent desiderata. "With 

 the new instrument former work will be confirmed and rendered quanti- 

 tative, while it is hoped to deepen and extend it in such manner as to lay 

 sure the foundations of this new branch of practical science. 



An Experimental Investigation into the Role of the Blood Fluids 

 in the Intracellular Digestion of Certain Bacteria and Red 

 Blood Corpuscles. 



By S. E. Douglas, M.E.C.S., L.R.C.P. (Loud.), Captain I.M.S. (Eetired), 

 1st Assistant, Bacteriological Department, Medical Eesearch Com- 

 mittee, National Insurance Act. 



(Communicated by Sir Almroth Wright, F.E.S. Eeceived June 3, 1916.) 

 (From the Inoculation Department, St. Mary's Hospital, Paddington, W.) 



Any observer who may have carried out a number of experiments on 

 phagocytosis in vitro, especially when some members of the coli group, or 

 the gonoeoccus, have been the microbes under observation, cannot fail to 

 have been struck by the marked intracellular digestion which is seen in the 

 microscopical preparations made in the course of these experiments. 



This intracellular digestion is evidenced by many of the organisms 

 ingested by the leucocytes appearing as ill-stained, swollen shadows lying 

 in vacuoles. 



Further, several independent workers in this laboratory, when working 

 out the opsonic index in the case of glanders, noticed that those glanders 

 bacilli which had been ingested by the leucocytes after being acted on by the 

 normal human serum showed from their appearance in the opsonic films many 

 more signs of digestion than those which had been acted on by the patient's 

 serum, and this was the case quite independently of the value of the opsonic 

 index of the patient's serum, as is shown by the fact that on occasions when 

 this was especially noted the opsonic indices were 2'6, 27, 1*7, 2*3, and 0'96 

 respectively. Another observation bearing on this subject, and one which 

 many workers may have noticed, is that the gonococci seen in the leucocytes 

 contained in specimens of gonorrhceal pus are sharp cut, taking the stain 

 evenly and deeply, whereas in specimens made for the determination of 



