REPORT ON DOURINJ. 59 



The sixth day specimens showed a general diminution, in that 

 the number of mature trypanoeomata fell to one- tenth of the 

 number seen on the fifth day. During the seventh, eighth, and 

 ninth days of the wheal, no mature organisms were discovered ; the 

 developmental forms, however, attained a maximum in number on 

 the seventh, and gradually decreased during the two following 

 days, the ratio of the actual numbers of developmental forms for 

 three days being 7, 4, and 2 respestively. On the 27th August, 

 the day following the disappearance of the above plague, when 

 examining several blood specimens drawn from the area previously 

 occupied by the plaque, I found one trypanosoma only and this was 

 undergoing longitudinal segmentation. 



It would appear from the above (1) that one trypanoeoma 

 undergoing division was unable to restart the process of plaque 

 formation, may be its premature removal stopped the further 

 development of the plaque. 



(2) On the day after the disappearance of the plaque, when 

 only a slight thickening of the part remained, either the whole 

 of the toxin had been eliminated from the area or sufficiently pure 

 blood or eero-sanguinous fluid was then present to allow of a develop- 

 mental form being changed into a mature trypanosoma, and 

 later to favour its segmentation. 



(b) The flat disc-shaped cutaneous plaque. The plaque No. 12 



brought forward as an instance, appeared on the B. flank of 



Kilngarth during the night and was observed on the morning of 



the 21st May 1903. It gradually increased in dimensions from 



the 23rd to the 27th (T25 inches diameter) and from the 28th 



to the 31st May became flatter. On the 1st June it had slightly 



decreased in diameter and continued to do so until it finally 



disappeared on the 5th. The trypanosoma was discovered in blood 



drawn from the centre, on the first and second days after the 



eruption of the plaque. On.the following day, 103 mature protozoa 



were found in one cover-gin ss preparation of blood collected from 



the same spot. The organisms increased and then gradually 



decreased in numbers and were absent by the 6th day. On this 



latter date the plaque had increased in one direction only towards 



the "W. j and blood drawn from small punctures in the N. E. E. 



