THE HAEMOFLAGELLATES 



219 



This peculiar feature of Trypanosomes differs in one or two 

 important respects from the somewhat similar phenomenon of 

 agglutination in Bacteria. The Trypanosomes do not in the 

 slightest lose their mobility during the process. Each individual 

 continues active movements, its flagellum lashing away at the 

 periphery, and appears to be making strenuous endeavours to escape. 

 Again, a rosette is able to become disagglomerated ; a bacterial 

 cluster or agglutination, on the other hand, is never dissolved. 

 Disagglomeration is appar- 

 ently in consequence of the 

 retention of the power of 

 movement by the parasites. 

 Sometimes all the indi- 

 viduals, apparently quite 

 unaltered morphologically, 



FIG. 13. 



Agglomerated cluster of 

 male forms of Trypanomor- 

 pha noctuae in the intestine 

 of the gnat. (After Schau- 

 dinn.) 



FIG. 14. 



A, binary union or agglomeration of T. 

 lewisi. B, primary rosette of the same parasite. 

 (After L. and M.) 



become thus dispersed. At other times disagglomeration is only 

 partial, a certain number of the more feeble Trypanosomes remaining 

 together and slowly dying. If the agglomerating serum is very 

 powerful, however, or if the biological conditions remain unfavour- 

 able, the rosette does not break up and the parasites at length 

 die off. 



The significance of the process has yet to be ascertained. By 

 some it is regarded as a purely involuntary proceeding on the part 

 of the parasites, and brought about more or less mechanically. A 

 suggestion put forward by Lignieres (54) is not without interest, 

 particularly when the recent work of Calkins on the essential 

 meaning of fertilisation is borne in mind. This author considers it 

 quite probable that, as a result of the close intimacy, a molecular 

 interchange goes on between the associated individuals, which may 

 have a stimulating or recuperative value. 



C. Abnormal and Involution Forms. Involution and degenerative 

 phases of Trypanosomes have received attention and acquired an 



