66 REPORT ON DOTJRINE. 



toxin farmed by them increases and the vasomotor disturbance 

 becomes more marked, as evidenced by the increase in area and swell- 

 ing of the plaque, until finally the mature forms gradually succumb to 

 the toxin. "When all the mature forms are destroyed, then during 1 a 

 period of several days only the developmental forms ar^ discoverable 

 in the sero-sanguinous fluid taken from a plaque. Gradually the 

 toxin is eliminated from the plaque, the vaso-motor paresis lessens 

 a-nd finally disappears, the exuded serum is then taken up by the 

 tissues, and the plaque disappears. 



XIII. Blood or sero-sanguinous fluid taken from a plaque is 

 bactericidal ' in vitro.' If the blood or sero-sanguinons fluid be 

 collected from a well-marked Dourine plaque, from which the 

 mature trypanosomata have disappeared, and it be mixed with a 

 small quantity of blood containing mature trypanosomata from a 

 second animal suffering from the same disease, it will be observed, 

 on microscopical examination of the mixed fluids, that the try pano- 

 somata are sooner or later acted upon by a something contained in 

 the serum, that their movements become slower and slower and 

 finally cease, and that later a granular disintegration of the parasite 

 follows. On the other hand, the organisms in the second or control 

 specimen of blood containing trypanosomata without added serum 

 retain after many hours almost the same energy in their movements 

 as when the blood was first drawn and submitted to examination. 



XIV. Conclusions.- Whenever a cutaneous plaque appears 

 during the course of Dourine, thetrypanosoma or its developmental 

 form will be found in it if a thorough microscopical examination 

 of stained specimens be made. 



During the initial stage of plaque formation in any part of the 

 body the trypanosoma is present there. At a later date, as long as 

 03d ama persists, trypanosomata or their developmental forms are 

 present somewhere in the cadematous area. 



Mature trypanosomata may not be discovered in the semen of a 

 stallion suffering from Dourine; if stained specimens be made and 

 careful search be carried out, other forms than that of. the mature 

 protozoon will be discovered. 



The cerebro-spinal fluid of animals which have succumbed to an 

 acute form of the disease accompanied by nervous symptoms 

 contains the developmental forms of the organism. 



