506 Dr. H. B. Fantham. Herpetomonas pediculi, n, sp., [Nov. 24, 



Some of the lice so obtained were dissected, and found to contain Herpeto- 

 monads. The adult lice were isolated into glass tubes, containing small 

 fragments of white woollen material. They clung to the material, and 

 excrement from them adhered to it. Examination of the said excrement 

 in a very few cases showed non-flagellate stages of the parasite. Lice, thus 

 known to be infected, were then paired, as also were lice that were apparently 

 uninfected. The parent lice were kept in closed tubes in contact with my 

 body, and were fed twice daily, either on my arm or on the back of my hand. 

 They fed greedily, often evacuating fasces as they fed, and at times even 

 unaltered fresh blood. The eggs from these lice were kept also in tubes, and, 

 when the larvae hatched, they were treated in the same way as the adults. 



Detailed examination was made of the eggs, larvae, and adult lice, and it 

 was found that bred lice from parents known to be infected were parasitised 

 by H. pediculi. Though clean lice bred clean, the young ones became 

 infected when they came in contact with the faeces of infected lice. 



Again, faeces known to be infected were smeared on spots at which 

 uninfected young lice were allowed to feed. Three days later, control 

 insects showed no flagellates or other form of the parasite, while those fed at 

 infected spots contained active flagellates when dissected. 



The sole food supply of the bred lice was my own blood. Cultures of my 

 blood on Mathis' modification of Novy and MadSTeal's medium have never 

 yielded any flagellates of any sort. 



The percentage of infected lice is not a high one — I have dissected as 

 many as 50 lice at a time without finding Herpetomonads — nor can the 

 infection be described as heavy ; 300 Pediculi were examined, of which 25 were 

 found to be infected. Much time has been devoted to the examination of 

 fresh material, which is absolutely essential if the life-cycle is to be followed 

 with exactitude. The gut of the louse was divided into small serial portions, 

 each of which was finely teased and examined in physiological salt solution. 

 Observation of the living organisms was supplemented by examination of 

 thin smears of the gut contents, teased intestinal wall, and other organs, and 

 long search was made for possible intracellular stages. 



Wet fixation with osmic vapour, followed by absolute alcohol, was used, 

 and coloration with Giemsa's or other modification of the Eomanowsky 

 stain. Very dilute solution of methylene blue was of use as an intra vitam 

 stain. 



It may be noted that lice dissected when several hours had elapsed since 

 the last feed showed the parasites better than recently fed ones. The 

 presence of much blood in the gut interferes with the study of the living 

 organism, as well as adds to the difficulty of staining. 



