62 PEACTICAL PAEASITOLOGY 



and corresponds to the flagellar nucleus of Trypanosomes. Both 

 nuclei are readily seen in the asexual forms and in the macrogametes. 

 In the microgametes, however, the nuclear structure is more difficult 

 of recognition, and this is especially the case with the full-grown 

 organism. The nucleus will be found to have split up into eight double 

 nuclei, which are crowded together in the centre of the organism, and 

 each one of which consists of a principal and a flagellar nucleus. 

 From these, eight daughter microgametes are formed. 



Free-living forms should be sought for at night in the internal 

 organs (liver, spleen, bone-marrow) of birds, the blood of which 

 contains asexual forms in large numbers. According to Schaudinn, 

 the parasite projects a flagellum and assumes a Trypanosome form 

 under the following conditions : (1) During the six days' period of 

 growth for the purpose of migrating from one red blood corpuscle to 

 another (fig. 16). (2) At the end of the period of growth for the 

 purpose of reproduction, this process consisting in longitudinal fission 

 repeated several times in quick succession. Multiplication by rapidly 

 repeated binary fission takes place in another species of Hcemoproteus, 

 very prevalent in Brazilian doves. But in this instance it takes place, 

 not during the free-living Trypanosome stage, but in the interior of the 

 leucocytes, where numerous minute structures resembling Leishmania 

 are formed. These are likewise observed in the internal organs only, 

 and are most frequent in the lungs. 1 



As we have already stated, the processes of fertilization are easily 

 followed in Hcemoproteus. A drop of blood containing a large number 

 of parasites should be diluted with a little water and examined 

 immediately, either as an ordinary cover-class preparation or in the 

 form of a hanging drop. 



The blood should not be diluted to such an extent that only single 

 corpuscles are left in the field of vision, or the parasites will become 

 damaged by the addition of so large a quantity of water. Manson 

 says that it is sufficient to breathe well on the cover-glass before 

 applying the drop of blood. The right degree of dilution is easily 

 judged, however, after a little practice. Instead of water, Hartmann 

 uses one part serum and nine parts 0'6 per cent, normal saline solu- 

 tion, one drop of the mixture being added to each droplet of strongly 

 infected blood. The real importance of this dilution is, obviously, 

 the change which it brings about in the osmotic conditions. If 

 undiluted blood is examined under conditions which permit of the 

 access of air, the phenomena of fertilization will take place as the 

 result, apparently, of the slow evaporation of water. But if undiluted 



1 H. de B. Arago, " Ueber den Entwickelungsgang und die Uebertragung von 

 Hcemoproteus columbce" Arch. f. Protistenkunde, vol. xii, parts 1 and 2, 1908, pp. 

 154-167. 



