112 BIOLOGY OF THE PROTOZOA 



of the little owl (Glaucidium [Athene] noctuae). Schaudinn's descrip- 

 tion and figures of the history of the kinetic elements at the base 

 of the flagellum have been cited and copied in practically every 

 text-book dealing with the Protozoa and have had a wide influence 

 in theoretical protozoology. Other keen observers, however, have 

 sought in vain for evidence corroborating this history. In the 

 absence of such confirmation and in view of the multitude of differ- 

 ent observers who find a simpler explanation in many different 

 types of trypanosomes, including that of the little owl (see Minchin, 

 Robertson, Sergent, et al.), Schaudinn's interpretation and conclu- 

 sions can be accepted only with many reservations. 



The essential point in Schaudinn's description was the origin by 

 heteropolar mitotic division of the nucleus of a recently " fertilized 

 cell," of a larger nucleus which becomes the nucleus of the cell, 

 and a smaller nucleus which forms the kinetic complex. This 

 smaller nucleus divides again by mitosis, also heteropolar, the smaller 

 portion becoming the basal granule which forms the flagellum and 

 the "myonemes" of the undulating membrane, while the larger 

 portion remains intact as a homogeneous deeply-staining granule. 

 The contested points in regard to this phase of Schaudinn's work 

 are, first, the "fertilized cell" of the trypanosome, which is now 

 generally regarded as a stage in the life history of an entirely differ- 

 ent parasite of the little owl (Minchin enumerates no less than five 

 different types of protozoon parasites which may live simultaneously 

 in the blood of this owl). A second contested point is the origin 

 of the kinetic elements of the cytoplasm by mitosis. Other con- 

 tested points and untenable conclusions drawn from them have to 

 do with sex differentiation and parthenogenesis which need not be 

 considered here. 



It is not at all impossible that Schaudinn may have seen the emer- 

 gence of a kinetic element from the endosome of the nucleus as de- 

 scribed above in the case of Dimastigamoeba gruberi, and the similar 

 emergence of a basal granule or blepharoplast from a chromatoid 

 mass in the cytoplasm. The interpretation of such possible stages 

 as mitotic nuclear division, and the smaller products of such division 

 as nuclei, has led to numerous theoretical developments which have 

 only a narrow basis of fact. Two years after Schaudinn's paper 

 appeared, Woodcock translated it into English and conferred the 

 name " kinetonucleus " on the smaller body resulting from the 

 heteropolar mitotic division and the name " trophonucleus " on the 

 nucleus of the cell. Schaudinn himself was the first to announce 

 this binucleate character of the trypanosome body and the hypoth- 

 esis was taken up by his followers, Prowazek, and notably Hartmann 

 (1907). The latter developed the conception into an elaborate 

 view of original nuclear dualism upon the basis of which he created 

 a special group of the Protozoa including trypanosome-like flagel- 



