440 



TR YPA NO SO MI Dm 



Morphology. — ^This has been most carefully studied by Fantham 

 in 5. recurrentis, S. duttoni, and S. marchouxi, and he finds that they 

 have long, narrow bodies, bent into many spiral coils, enclosed in 

 a firm periplast, with a very tenuous membrane, which is often in- 

 visible. The nucleus consists of granules of chromatin distributed 

 along the body. 



Life-History.— Multiplication can take place by longitudinal and by 

 transverse division, and also by multiple transverse fission, in Which 

 case the protoplasm concentrates around the chromatin masses, 

 giving rise to a number of round or oval granules, probably the 



same as the infective granules 

 of Fry and Balfour, which are 

 known to escape from one end 

 or the other of the periplastic 

 sheath when in the internal 

 organs. These infective 

 granules enter the red cells, 

 and divide into a number of 

 merozoites, which escape from 

 the red cell and enter the 

 liquor sanguinis; but their 

 further development is un- 

 known, though it is possible 

 that they become spirochaetes. 



Fantham's observations 

 have confirmed this granule 

 stage of the life-history, but 

 it must not be forgotten 

 that every granule seen in a 

 spirochaete is not an infective 

 granule, which our own ob- 

 servations support. 



Minchin regarded these granules 

 Fig. 126. — Life-Cycle of Spiroschau- as true endogenous chromidial 

 dinnia marchouxi Nuttall. buds, and considered therefore 



that the term infective granule 

 (After Hindle, from the Journal should be replaced bv the 

 of Parasitology.) term ' endogenous ' bud forma- 



tion. 



The life-history of a spiroschau dinnia in the invertebrate has been traced by 

 Leishman for S. duttoni in the tick, Ornithodoros moubata, and his account has 

 been confirmed by Balfour, Hindle, Blanc, Fantham, and others. 



The Spiroschaudinnics , on entering the tick, penetrate the gut wall, and on 

 reaching the body cavity divide by multiple transverse fission into minute 

 ovoid or rod-like bodies, which reach the ovary and become incorporated 

 with some of the ova. In this situation they are not often infective. When 

 laid, the egg only contains a few ovoid bodies, but in three to five days* in- 

 cubation, when the Malpighian tubes have begun to develop, ovoid and more 

 elongate bodies may be seen therein. In six to seven days' incubation these 

 bodies have elongated and become bacillary, and may rupture the cell and 

 appear in the lumen of the tube. It is believed that these bacillary forms give 

 rise to spirochaetes either by elongation and growth, or by fusion of rods. The 

 recently hatched tick contains ovoid bodies, bacillary forms, and a very few 



