206 REVIEW — TROPICAL MEDICINE, ETC. 



Trypano- T. equiperdum as described by them. In T. lewisi, however, the inter-action between the 

 somiasis— extra-nuclear centrosome and the nucleus is followed by the formation of characteristic 

 continued multi-nucleated masses. These again are succeeded by the assumption of the peculiar 

 morphology of the round flagellated " latent body " which eventually passes into the 

 trypanosome form. One point specially noted is that whereas in the pathogenetic forms, 

 T. gainliipHse and T. efjniperdum, the phases of the life-cycles as they appear among the 

 trypanosomes do so nearly simultaneously among all the parasites existing in the blood at a 

 particular time, and thus mark successively the stages of the infection ; in the non- 

 pathogenetic form, T. lewini, all the stages of the life-cycle may be present and represented 

 by diti'erent parasites which are found in the blood at the same time. 



The authors note that in the case of all three trypanosomes mentioned they have quite 

 failed to find any evidence of the so-called males, females and other forms described by 

 Schaudinn. 



An interesting paper, and one of very considerable importance, is that by Novy, MacNeal 

 and Torrey' on the trypanosomes of mosquitoes and other insects. Some of their 

 conclusions are here tabulated : — 



1. Of the " wild " mosquitoes examined by us approximately 15 per cent, in one year, and about 5 per cent, in 

 tbat following, were found to be infected with flagellates belonging to two easily differentiated types. Crithidia 

 and Hrrpi'tomoiias. The percentage of infections is influenced largely by local and seasonal conditions. 



2. By the cultivation method it has been possible to isolate two of these flagellates, namely Crilhidia 

 fascicuJala and T. cu/icis ; and it has been shown that the plate method is applicable for the separation of 

 trypanosomes from the accompanying bacteria and yeasts. 



3. The organisms obtained in vilro correspond to those observed in vivo, and hence the intestinal types 

 represent true cultural forms. 



4. The two types are common in other insects, and, instead of being classed as distinct genera, they should be 

 placed under the trypanosomes. 



5. The mosquito flagellates are not stages of intracellular organisms, but are probably parasites peculiar to 

 the insects. 



6. The inocul.ation of available experimental animals with the C'rithiiliii and fferpetomonas has given 

 negative results. 



7. The trypanosomes which are at times present in ticks are not developmental forms of Piroj)lasina. It has 

 already been shown that the trypanosomes in tsetse flies are not related to T. rjaiiiMeme or T. Bnicci. 



8. The possibility of the tryj^anosomes of birds and other vertebrates developing in the gut of insects, while 

 not excluded, has not been demonstrated. In the mosquito, T. lewisi and T. briicei lose their infectiousness, 

 more or less rapidly, but the enfeebled organism may survive in the gut for 36-48 hours. The conditions in the 

 digestive tube of insects is not as favourable as in the test-tube, and this fact goes to show that insect carriers, such 

 as tsetses, are mere passive hosts. 



Morax- has a paper on ocular manifestation in trypanosomiasis, and concludes that the 

 lesions, on account of their frequency and character, are of great interest. The appearance 

 of a non-ulcerated interstitial keratitis in animals may, in many cases, lead us to suspect 

 the existence of trypanosomiasis. 



This interstitial keratitis is provoked by the multiplication of trypanosomes in the 

 interlamellar spaces of the cornea. The proliferation of the parasite leads to an infiltration 

 of leucocytes, then a vascular development. These lesions may cause complete disorganisation 

 of the cornea. They may disappear, leaving very slight traces after them. This occurrence 

 is most common in animals which show a marked resistance to infection by trypanosomata. 

 This was the case in the goat attacked by Dourine or Nagana. Dogs, on the contrary, die 

 whilst the cornea is still completely opaque. 



The interstitial keratitis occurring in dogs inoculated with the Sudan tryj)anosome of 

 mules was described in the Second Eeport of these Laboratories. 



It is of interest to note that recently Yakimoff and Schiller' reported that rabbits, 

 guinea pigs, dogs, white and grey rats, but not white mice, can be infected by feeding with 

 Tri/paiKisfima letcisi and the trypanosomes of El-Debab (a disease of dromedaries in Algeria), 

 Nagana, Surra and Dourine. Experiments with the trypanosome of Mal-de-Caderas yielded 

 negative results. 



' Novy, P. Q., MacNeal, W. J., Torrey, H. N. (April 10th, 1907), "The Trypanosomes of Mosquitoes and 

 other Insects." Journal of Infectious Diseases (Chicago), Vol. IV., p. 269. 



'' Morax, V. (January 25th, 1907), " Manifestations oculaires an cours de Trypanosomiases," Ann. dc Vlnslitul 

 Pasteur, Vol. XX. 



^ Yakimoff, W. L., and Schiller, N. (1907), " Zur Trypanosomen infektion durch die Schleimhaut des 

 Verdaungstraktes." Cent.f. Jinkt. Aht I., Bd. XLIII., H. 7. 



