756 OEDEK: ACTINOMYXIDIIDA 



The individual parasite is a small ovoid body about 2-5 microns in length by 

 0-5 to 1 micron in breadth. At the end there are one or two chromatin-like granules. 

 In many respects it resembles a small yeast, but reproduction by budding has not 

 been observed. Levaditi and his co-workers believe that they have demonstrated 

 small cytoplasmic bodies (pansporoblasts), which give rise to the spores, and they 

 conclude that the parasite is a microsporidian, in spite of the fact that these parasites 

 have never been found in warm-blooded vertebrates. They have not demonstrated 

 the presence of a polar capsule and filament, while their account of the development 

 of the spore requires confirmation. It seems premature to conclude that the 

 oi-ganism is even a Protozoon. The writer in 1909 saw what was evidently the same 

 organism in sections of the brain and liver of a rabbit, but was unable to arrive at any 

 conclusion regarding its nature. Da Fano (1924) has given a good description of 

 the organism and the lesions it produces in the brain of rabbits in England, and 

 Smith and Florence (1925) its appearance in the kidneys. Goodpasture (1924) has 

 seen it in the lungs. 



Levaditi, Xicolau and Schoen (1924?>) suggest that the virus of rabies is probably 

 a microsporidian which enters the body in some invisible stage, and produces 

 eventually the Negri body. Manouelian and Viala (1924) go even further, and claim 

 to have demonstrated in the cells of the brain and salivary gland of dogs organisms 

 which are indistinguishable morphologically from those in the disease of rabbits 

 described above. They name the organism Encephalltozooii rabiei. Levaditi, 

 Nicolau and Sclioen (1924c), in a later paper, confirm the observations of Manouelian 

 and Viala, and claim that the Negri body is the cyst stage of the parasite. Ignoring 

 the specific name rabiei, they place it in the genus Gliigea as O. lyssce. Here, again, 

 there is no evidence that the organism is a microsporidian, as indeed Manouelian and 

 Viala suspect. 



The presence of the parasite in mice, whatever its true nature may be, introduces 

 another fallacy into experiments which involve the discovery of Lslshmania in the 

 organs of animals inoculated with insect flagellates (see p. .395). The figures of 

 Encephalitosoon cunieuU and the similar parasite of mice show how easy it would be 

 for such parasites, when seen in smears stained with Eomanovsky stain, to be mis- 

 taken for Leishmania. 



C. Order: ACTINOMYXIDIIDA. 



The parasites included in this order (=Actinomyxi(lia Stole, 1899), 

 which were first seen and named by Stole (1899), occur in aquatic worms. 

 The spores are complicated structures consisting of a capsule composed of 

 three valves, each of which may be drawn out into a long spine which may 

 be bifurcated, so that there is a definite triradiate arrangement (Fig. 324). 

 Three polar capsules are present, and the mature spore contains a variable 

 number of amoeboid infective agents, often referred to as sporozoites. 

 The Actinomyxidiida have been studied by Stole (1899), Leger, L. (1904a), 

 Caullery and Mesnil (1905a), Ikeda (1912), and Mackinnon and Adam 

 (1924), to whose researches most of what is known of these parasites is due. 

 The development of the spore is a complicated process which resembles 

 that of the spores of Myxo sporidi da. It has been traced in certain species 

 by Caullery and Mesnil (1905a), Ikeda (1912), and Mackinnon and Adam 

 (1924). There are, aosording to Ikeda, the following five genera: Tetracti- 



