Februaet 9, 1906.] 



SCIENCE. 



207 



doubt the basis of curative treatment in 

 relapsing fever and in tick fever of Africa. 

 It is the intention of the authors to work 

 on the practical application of the principle 

 discovered. 



Spirochcetal blood which has been di- 

 luted with ten parts of salcitrate solution 

 and filtered through a Berkefeld filter, 

 under a pressure of fifty pounds, yields a 

 filtrate which, when injected into white 

 rats, produces typical spirochsetal infec- 

 tion. The spirochsetes, as in the case of 

 cultures of Trypanosoma Lewisi, are filter- 

 able through a Berkefeld filter. Impor- 

 tance of this fact in its bearing upon the 

 so-called ultra-microscopic organisms was 

 pointed out. 



All attempts thus far to cultivate the 

 spirochsete on blood agar have failed, but 

 this subject will be followed further. The 

 spirochffites multiply by transverse divi- 

 sions and show other characteristics which 

 belong to bacteria. On the other hand, the 

 transmission of spirochsetal diseases by in- 

 sects, the persistence of the organisms in 

 such insect hosts for months, and the infec- 

 tion of the eggs of such insects, are the 

 main facts known at present which point 

 to a possible protozoal nature of the para- 

 sites. 



The persistence of the spirochsetes of tick 

 fever in the blood of rats for three to eight 

 days, as shown by Button and Todd, would 

 indicate that this organism, though closely 

 related, is, nevertheless, different from that 

 studied by us. It goes to show that tick 

 fever of Africa and the relapsing fever of 

 Europe are due to different species of 

 Spirochcetes. 



This paper will shortly appear in the 

 Journal of Infectious Diseases. 



Mosquito Trypanosomes: F. G. Novr, "W". 

 J. MacNeal and H. N. Toerey, Univer- 

 sity of Michigk'h, Ann Arbor, Mich. 

 Iri"^ a previous paper on bird trypano- 



somes it was pointed out that these organ- 

 isms grew readily in the test tube on blood 

 agar and that the resulting forms resem- 

 bled the fiagellates which Schaudinn found 

 in the gut of mosquitoes which had fed on 

 owls infected with Halteridium and with 

 H. Ziemanni. In other words, the position 

 taken was that the flagellates observed in 

 the mosquitoes did not represent stages in 

 the life history of intracellular parasites, 

 but were actually cultures in vivo of tryp- 

 anosomes present in the blood of the birds 

 used. In confirmation of this position it 

 was desirable to show that trypanosomes 

 could actually grow and multiply in the 

 gut of mosquitoes and that such forms 

 actually did correspond to those which 

 would be obtained in vitro. 



Accordingly, large numbers of mosqui- 

 toes were captured along the river bank 

 and allowed to feed on perfectly clean ani- 

 mals, such as rats, guinea-pigs and pigeons. 

 At varying intervals, thirty-six to seventy- 

 two hours after feeding, the contents of 

 the stomachs of the mosquitoes were ex- 

 amined in living and in stained prepara- 

 tions and cultures on blood agar were made 

 at the same time. Of more than 800 

 mosquitoes which .were examined in this 

 way about 120, or 15 per cent., were found 

 to have a flagellate -infection of the in- 

 testinal tract. In some this was very 

 marked; large masses of rosettes, flagella 

 inside, completely filling the lumen of the 

 tube. 



Several distinct forms . of trypanosomes 

 were met with; the most common of thesR 

 was a Herpeiomonas (probably Herpeto- 

 monas suiulata) and Crithidia fasciculata. 

 Owing to the large numbers of bacteria 

 usually present much difficulty was experi- 

 enced in obtaining cultures of these flag- 

 ellates. Eventually, however, the Her- 

 petomonas was isolated in mixed culture 

 associated with a minute eoficus, while the 

 Crithidia was obtained in association with 



