H^EMOPROTEUS 63 



blood is examined under conditions which do not permit of the access 

 of air, these phenomena will not be observed. 



Temperature conditions are also a factor of importance. A 

 temperature of about 20 to 25 C. is the most favourable ; tempera- 

 tures of about 18 C. or under, and 30 C. or over, are unfavourable. 



The first point to observe in the finished specimen, is the way in 

 which the gametocytes become rounded and escape from the red 

 corpuscles by bursting them open. In the microgametocytes, active 

 streamings of the protoplasm commence, which cause the knoblike 

 plasmic process to appear and disappear, and which lead to the rapid 

 formation of microgametes. These spring suddenly as long hyaline 

 threads, four to eight in number, from the body of the parasite. They 

 immediately commence violent thrashing movements, by which they 

 finally succeed in freeing themselves from the parent organism, when 

 they writhe away. In the meantime, though this is not so easily 

 followed, a change has taken place in the macrogametocytes. This 



abed e 



FIG. 17. Final stages of development of the sex-forms of the parasite of human 

 malignant malaria (Laverania malarice or Plasmodium immaculatum) . a, 6, Female ; 

 ce, male. 



consists in the reduction of the nucleus, by which the macrogameto- 

 cyte becomes a sexually mature macrogamete. The macrogamete is 

 now fertilized by the agency of a microgamete. The copulation of 

 the two sexual forms is followed by a period of rest. Then, at a spot 

 upon the surface of the new individual, a conical protruberance begins 

 to appear, which gradually increases in size and from which, after 

 a quarter to half an hour, the long ookinet proceeds, which moves by 

 means of writhing movements forwards. The entire process may 

 be observed inside three-quarters to one hour (figs. 17 and 18, 13 to 17}. 



The reproductive process can also be followed in fixed and coloured 

 specimens. A number of glass slides are prepared with diluted blood, 

 as described above, and placed in a damp chamber. They should be 

 fixed singly and at suitable intervals. 



Under normal conditions the fertilization of Hcemoproteus noctuce, 

 takes place in the stomach of Culex pipiens. The artificial infection 

 of the mosquito is successful, however, in only a small proportion of 

 cases, and the operation requires so much time and patience that the 

 method is of little use, either to the student or for purposes of 



