50 THE ANIMAL PARASITES OF MAN 



(macrogametes) have been fertilised by the males (microgametes) 

 they sporulate. The sporozoites ultimately collect in the salivary 

 glands of the mosquitoes, and are inoculated into the blood of 

 man or bird by means of the bite ; here they again multiply by 

 schizogony and thereby cause the disease. 



Accordingly, certain species of mosquitoes are the definitive hosts 

 of the malaria parasites, because the adult stage is passed in them ; 

 and warm-blooded animals are the intermediary hosts. 



Haemosporidia, in . addition to their incidence in man and birds, 

 also occur in monkeys [Kossel (23)] and bats, [Dionisi (24)], the 

 alternative hosts, however, of these species are not yet known. 

 It is doubtful whether the parasites causing the Texas fever of 

 cattle (Piroplasma bigeminum, Smith), which Babes discovered and 

 on which Celli and Santori recently reported (C. /. B. P. u. /., 

 1897, xxi., p. 561), are real Haemosporidia. According to Babes, 

 Laveran and Nicolle, analogous forms occur in sheep ; according 

 to Piana, Galli-Valerio, Leblanc, Marchoux, Nocard and Almy, 

 they are found in dogs. (The two last-mentioned authors, in 

 fact, suggest that -ticks play a part in the piroplasma infection 

 of dogs), according to Laveran they occur in horses, and according 

 to Lignieres several species of Piroplasma live in cattle. 1 



The development of the Haemosporidia of cold-blooded animals, 

 reptiles, amphibia and fishes, seemed amply known through Labbe's 

 great work (14) ; later works did not with certainty disclose any 

 other circumstances, though in consequence of the discoveries con- 

 cerning the malaria parasites of warm-blooded animals we began to 

 doubt the completeness of our knowledge of the Haemosporidia of 

 cold-blooded animals. These doubts have been fully justified by the 

 appearance of the only book treating of Lankesterella minima ( 

 Drepanidium ranarum) by Hintze (25), for in these parasites 

 there is an alternation of generations, without, however, a change 

 of hosts. Schizogony and sporogony, according to the author, go 

 on simultaneously within the same host, and the oocysts filled 

 with sporozoites, which mature in the intestinal epithelium of the 

 host, make their escape with the contents of the intestine into 

 the open, whence they cause the infection of other hosts, probably 

 per os. 



LITERATURE. 



(i) CHAUSSAT. Des hematozoaires. These, Paris, 1850. 



RAY LANKESTER. On Undulina the Type of a New Group of Infus. (Quart. 

 Journ. Micr. Sc., 1871, xi., p 387). 



1 Malignant jaundice in dogs is due to Piroplasma canis, carried by the Tick 

 Haemophysalis leachii. Audouin. African coast fever in cattle is due to Piroplasma 

 parvum (Theiler), and is carried by Rhipocephalus appendiculatus (Neumann), and 

 /?. simus (Koch). In horses and donkeys we get Piroplasma equi. (F.V.T.) 



