222 THE HAEMOFLAGELLATES 



case of single forms the body becomes stumpy (Fig. 15, C-E), losing 

 almost entirely its trypaniform shape, and ends by being ovoid or 

 like a ball (c, H, L) ; l the flagellum is limp and inactive and partially 

 coiled up (j). In other cases, quite irregular multiplication occurs, 

 accompanied by incomplete cytoplasmic division, leading to the forma- 

 tion of distorted multinucleate and multiflagellate bodies (Fig. 16, 

 A G). Lastly, various fusion -forms may be met with, masses of 

 Trypanosomes gradually losing their distinctness and constituting 

 large plasmodia (Figs. 16, L; 15, s), made up of a great number of 

 nuclei embedded in a common cytoplasmic matrix. 



If the organisms remain subjected to the unfavourable influences, 

 or if involution has reached too advanced a stage, death and dis- 

 integration result. The cytoplasm is the first to disappear, becoming 

 hyaline and colourless, and refusing to stain up. The nucleus 

 rapidly follows suit. The most resistant elements are the kineto- 

 nucleus and flagellum, which may persist long after other traces of the 

 organism have vanished (Fig. 15, p), the former as a little thickening 

 at one extremity of the latter ; sometimes the flagellum alone is left. 



5. MULTIPLICATION. 



Binary longitudinal fission is, probably, of universal occurrence, 

 and appears to be the usual method of multiplication ; though 

 Trypanosoma lemsi, at any rate, possesses another method in 

 addition, namely, rosette -like segmentation. 



The process of fission begins with the division of the nuclear 

 and locomotor apparatus, but the actual order of division of these 

 different organellae appears to be very inconstant and variable. 

 As a rule, the kinetonucleus leads the way, but sometimes the 

 trophonucleus may. The duplication of the flagellum begins at 

 its proximal end, that which is in relation with the kinetonucleus. 

 Until lately the process has always been considered as an actual 

 longitudinal splitting of the flagellum, following upon the separation 

 of the two daughter-kinetonuclei. Now and again examples are 

 met with in which the duplication of the flagella has taken place 

 before the kinetonucleus has divided. It seems probable that it 

 is really the division of the kinetonuclear centrosome which is the 

 essential prelude to the division of the locomotor apparatus. This 

 flagellar splitting has been described either as extending to the 

 distal end of the undulating membrane, after which the two halves 

 separate (Fig. 17, c), or as being practically limited to the root- 



1 It is here, if anywhere, that there might be a possibility of regarding as involution- 

 forms phases which really belong to the normal life-cycle ; e.g. rounded-off, resting 

 phases (cf. the " resistant forms " of Holmes and others). In such, however, the 

 flagellum would doubtless be absent, while the nuclear elements and cytoplasm would 

 be as usual ; in fact, the parasites might well show a resemblance to the Leishman- 

 Donovan bodies (cf. pp. 255 et seq.). 



