SI'IEOCH.ETOSIS OF SUDANESE FOWLS 105 



There can, I think, be little doubt that it is indeed these granules derived from 

 spirochastes which enter the erythroblasts of the fowl in which, possibly because of some 

 capsule they secrete, they can be stained by the Eomanowsky method. They appear at first 

 as tiny specks and rapidly become the ring or large solid or irregular forms which have been 

 described and which pass on to the "spore " bodies, thus completing a cycle of schizogony 

 or a special cycle, which ends by the discharge of tiny granules (merozoites) into the 

 liquor sanguinis. As a result of these later observations I have abandoned the erroneous schizogony 

 idea, which I quite failed to prove, that the bodies are directly formed from the spirochaetes 

 and that the larger forms are the early forms due to the parasites coiling up and 

 contracting in the red cells. The supposition was perhaps pardonable as spirochetes can 

 and do enter and leave the red cells and the invasion of the red cells by the granules does 

 not appear to take place in any regular manner. There do not seem to be any 

 "generations" of bodies, all completing their cycle of development at or about the same 

 time. The entry and the maturation are apparently irregular as regards time and hence 

 a confusing picture is presented, J'oung forms, ring forms, and spore forms all occasionally 

 being present in one film. A study of some of the case records, however, would seem 

 to give some idea of the usual duration of the cycle. Perhaps renewed study of the 

 infection in the light of these discoveries will yield further information as to this non-sexual 

 cycle. What is its object ? This is not altogether easy to answer for one has not yet seen 

 spirochetes develop from the tiny granules set free by the rupture of the schizogony forms 

 in the red cells. True there are indications that this occurs but the mechanism of develop- 

 ment as yet remains unknown. Again only a certain proportion of the granules discharged 

 by the spirochaetes pi-obably enter red cells. What happens to the rest? From the study Bearing of the 

 of Levaditi sections they appear to be stored up in the internal organs. Is it from these observations 

 that fresh spirochaetes develop and does this in some measure explain the mechanism of ^ i,ocha:tai 

 relapse not only in this fowl spirochsetosis but in human tick fever ? Does it also perhaps infections 

 throw light on the chronicity of such disorders as syphilis and j'aws? The granules 

 discharged by spirochaetes are resistant, much more so, I think, than the parasites from 

 which they come. One can cure a fowl entirely by "606," presumably by killing all the 

 spirochaetes in it outright. If, however, too small a dose be given, granule discharge begins 

 and unless the amount of "606" present is sufficient to kill these infective granules, the 

 cycle of schizogony starts, just as it starts under natural conditions if the leucocytes or the 

 protective fluids or anti-bodies of the bird have not proved powerful enough to destroy 

 all the spirochtetes. 



It would seem to be a protective process on the part of the parasites and may 

 also be connected in some manner with the cycle in the tick, but it is little use theorising, 

 and the various questions to be settled will have to obtain their answers by the 

 application of these newer methods and bv prolonged and careful observations. 



■ ^ " Importance of 



It would seem probable that these infective granules have not previously been noted, the dari<-ficki 

 partly because they can only be well seen by the dark-field method and partly because '"''"'°'' 

 when free they do not appear to stain, at least with any certaioty, by Eomanowsky. 

 This is a very curious thing, but it would seem to be undoubtedly the case. 



The fact that one is apt to get stain deposit by the Levaditi process and even by 

 its modifications adds to the difficulties of the work, which in any case has shown that 

 it is by the study of the lii-imj parasite that progress is chiefly made. At the same 

 time the Yamamato modification, slightly altered, has been of signal service. 



As this paper has to go to press, it is only possible to indicate along what lines further 

 work is proceeding. 



