66 



MICROBES AND TOXINS 



of chromidia. The nuclei of the Cyanophycese have been the 

 subject of similar disputes; in these inferior algse also the 

 existence of a chromidial nucleus is admitted, quite distinct 

 from the metachromatic bodies. 



Fig. 30. — Bacilhts maximus buccalis. (After Swellengrebel.) 



The spiral filament represents a system of chromidia in process of division 



(4 and 5). 



Reproduction and Sex. — A species is said to possess 

 sex when fertilisation occurs by the fusion of two nuclei 

 differentiated into male and female. 



In the haematozoa of malaria the sexual act takes place 

 in the body of the mosquito by the conjunction of the 

 flagellum and the female cell, and at this point the sexual cycle 

 begins. 



Since Schaudinn's discovery of the trypanosome forms in 

 the cycle of certain haematozoa closely related to those of 

 malaria, one must admit the existence of male and female 

 forms in the case of trypanosomes. Besides the asexual 

 multiplication by longitudinal division there would thus exist 

 among trypanosomes true sexual reproduction. 



Among the fungi the ovum, the complete reproductive form. 



