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



While it is quite true that certain trypanosoines, e.g., T. lewisi, assume 

 a Herpetomonas-like form in cultures, yet they are not then under exactly 

 natural conditions. Further, they may be considered as reverting to the 

 type from which it seems probable that they have originated, namely, 

 primitive Herpetomonads which have undergone morphological changes and 

 in process of time have evolved the trypanosome type when inoculated into 

 the vertebrate host. 



With regard to H. pediculi, I do not think that there is any doubt that it 

 is a flagellate, natural to and parasitic in the insect host, and that it has no 

 connection with a human trypanosome, pathogenic or non-pathogenic. 

 In support of this conclusion, I cite the following facts and experiments : — 



(1) At various times during the past three years, I have fed lice on my 

 blood from the time of hatching until they died. A tsetse fly transmitting 

 Trypanosoma gambiense is at first limited in its period of infective inoculation. 

 Lice might also be similarly limited, but, owing to the method of feeding 

 adopted, no question of the lice not having fed at their infective period can 

 be entertained. In spite of repeated feedings of lice, my blood shows no sign 

 of trypanosomes, whether tested by ordinary microscopical examination of 

 films, by thick films or by cultural methods, and the period covered by the 

 experiments is ample to have allowed of full development of trypanosomes, 

 were H. pediculi a phase of one. 



(2) Artificially infected lice have been fed simultaneously. The result of 

 mass feeding surely should have been sufficient to produce some indication 

 of trypanosomes, were any present. No such indications have been found, 

 even after inoculation of my blood into susceptible animals like white rats. 

 (Animals examined for six weeks after inoculation.) 



(3) The experiment of inoculating rats with the contents of the gut of lice 

 containing H. pedicidi has given no positive results whatever. The rodents 

 remained perfectly healthy, nor did cultures of their blood, or thick film 

 examinations, yield any trace of trypanosomes. 



(4) Cultures of the gut contents of infected lice showed no further stage in 

 the life-history of the parasite. 



(5) The methods of infecting larvae and adults of P. vestimenti with 

 H. pediculi have been briefly indicated in a preceding section. The same 

 contaminative method of infection has been observed under natural conditions, 

 and resembles that found in the case of some other insects, such as Pulex 

 irrilctns (adult and larva), infected with Crithidia pulicis (Porter, 1911) and 

 Nepa cinerea, harbouring Herpetomonas jaculum (Leger, 1902 ; Porter, 1909). 



Further, the well-de fined development of H. pediculi, with its pre-flagellate, 

 flagellate and post-flagellate forms, presents a cycle complete in itself, and 



