338 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Glugea lophii.* — Herr Al. Miazek discusses the cysts of Glugea 

 lophii Doflein, infecting the ganglion-cells and neurites of Lophius, and 

 gives reasons showing that Doflein's account j" of their formation cannot 

 be accepted. But what the correct version of the story is remains 

 obscure. 



Malaria and Mosquitos.J — The interesting account of the con- 

 nexion between malaria and mosquitos given by Major Ronald Ross 

 deserves a much greater space than can be afforded, but it may be 

 useful to recapitulate the stages of the life-cycle of this plasmodium 

 malariae. He starts with the amcebula, or that form of the parasite 

 which is seen in the red corpuscles, and which usually contains pigment- 

 granules, melanin, derived from the hsemoglobin. After a day or two 

 the amcebulae reach maturity and then become sporocytes. The spores 

 are set free and attach themselves to fresh red corpuscles. Other 

 amcebulae become gametocytes, i.e. male and female reproductive cells. 

 The sexual stage takes place in nature within the stomach of the 

 mosquito, but has been observed in vilro, while the presence of the 

 flagellated organism has been noted frequently. The flagella are long 

 motile filaments, spermatozoa in effect, if not in fact, and are extruded 

 from the male gametocyte. These, after the manner of spermatozoa, 

 having encountered a macrogamete, fertilise it, the result of the con- 

 nexion being a zygote. The zygote finds its way to the outer part of 

 the wall of the mosquito's stomach and rapidly increases in size. Here 

 its capsule thickens and its contents undergo subdivision, until the zygote 

 membrane becomes packed with thin spindle-shaped spores, termed 

 blasts, which are about 12-16 /x in length. When ripe, the zygote 

 membrane ruptures, and the blasts being set free, find their way to the 

 salivary gland, from which they are expelled along with the poison, 

 when the mosquito punctures the host. 



Insects and Blood-Parasites.§ — Dr. A. Libbertz gives an interesting 

 historical sketch of the present state of knowledge as to the part played 

 by blood-sucking insects in conveying blood-parasites from one host to 

 another. The following subjects are discussed, and the parasites and 

 the parasite-carrying insects figured and described : — The malarial 

 parasite of Southern Europe, and the more deadly form of the tropics, 

 which are probably not specifically distinct, and which both have a 

 secondary host in the mosquito ; the parasite of Texas fever (Pyrosoma 

 bigeminum), which is found in the blood of infected cattle in North 

 America, and is probably conveyed by Boophilus bovis ; the parasite of 

 Fly disease ( Trypanosoma) which is conveyed by the Tsetse fly ; the 

 remarkable parasites of the blood of birds (Halteridhim and Proteosoma), 

 whose life-history has only recently been worked out, and which appear 

 to be transported by mosquitos. These last are interesting because of 

 certain resemblances to malarial parasites, especially in the formation 

 of ciliated forms which play the part of spermatozoa. The bird parasites 

 are also of importance in offering greater facilities for research than the 

 malarial parasites. The illustrations are numerous and excellent. 



* SB. K. bobrnisch. Ges. Wiss., 1899, No. xxxiv., 8 pp. and 1 pi. 



t Cf. this Journal, 1899, p. 289. J Nature, lxi. (1900) pp. 522-7. 



§ Ber. Senckenberg. Naturf. Ges., 1899, pp. 105-18 (6 pis. and 46 figs.). 



