114 R - KUDO. 



the parasite becomes established in the new host animal, an 

 experiment was conducted. 



A number of larvae of Culex territans which had been collected 

 on July 10 and which were normal in appearance and behavior, 

 were set aside in a glass jar. At two o'clock in the afternoon, 

 three heavily infected larvae, cut into small pieces, were given 

 the larva", which fed willingly upon these fragments immediately 

 after the latter were placed in the water. Some of the larvae 

 fed only for a few seconds, others for several minutes. The 

 latter were removed one by one by means of a pipette as soon as 

 they ceased to feed, into another jar which was partly filled 

 with the rain water that had been standing by the laboratory 

 free from mosquito larva?. Twenty fed larvae were thus obtained 

 by three o'clock. I was sure that they had eaten certain portions 

 of the infected material; in fact, all of them showed, upon 

 microscopical examinations w r hich followed in from six hours to 

 four days, that they had devoured a large number of spores and 

 sporulating stages of the parasite. The majority of the larvae 

 which did not feed long or at all, were found pupated on the 

 following days. 



From another lot twenty larvae were selected as control 

 animals by macroscopical inspection of the group and a low 

 power microscopical examination of the individual larvae. 



On account of the comparatively simple organization of the 

 alimentary canal and its connected organs of the mosquito larva 

 and of the large dimensions of the protozoon, the microscopical 

 examinations of the material involved in the experiment both in 

 smears and in sections were carried out with greater ease and 

 certainty than that which I had experienced -in the case of the 

 infection experiments of Bombyx mori with Nosema bombycis 

 (Kudo, '16), where the conditions were reversed. 



In the study of the preparations related to the experimental 

 infection, Giemsa's stain seemed to be indispensable, since it 

 brought out the spores, particularly the sporoplasms with their 

 nuclei, of the microsporidian, sharply before the multitude of 

 other microorganisms of animal as well as plant nature, which 

 existed in the rain water and which found their way freely into 

 the alimentary canal of the insects. The distinction between the 

 latter and the emerged sporoplasms of the present microsporidian 



