71 



evidi'iico for which is exaniiiuMl ;ni(l ayain Ihi' [)r()oi's (h'chin-d 

 unsatistactory. The autliors have no douhl that the spirilhi are 

 taken up by the louse, and that for u time they seem to disappear 

 within their bodies, to reappear some days hitcr and then to dis- 

 appear again entirely. They say that the oiily reliable experi- 

 ments as to the transmission of recurrent fever by infected lice 

 have been made, not by allowing' them to bite the infected man or 

 monkey, but by the injection or subcntaneous inoculation of an 

 extract of infected lice. 



Despite the strong experimental evidence against the lians- 

 mission of tlie disease by lice, the authors are still of o])inion that 

 in another way the lonse plays a very important part, as siH)\vn hy 

 a case which occurred during tlie last epidemic in Tunis. A woi'k- 

 man from Tri])oli carried tlie infection to a " fondonk " in 'I'niiis, 

 of wlrich two rooms were occupied by a coh)ny of liis compatriots. 

 Very shortly afterwards every one of these was infectecl. There- 

 were no animals in the room whatevei' and the minute investiga- 

 tion of the furniture and other contents yicUh-d two fleas, one 

 bug (almost dried up), no specimens of Arf/ds or biting ticks of 

 any kind, and further, by reason of the time of year, no mosquitos 

 or' SfonKKfi/s. On the otlier hand, l)ody and head lice wer(> found 

 in enormous numl)ers. 



The authors continuing their investigations during the time that 

 the epidemic was spreading, recognised that this nu'thod oi i»io- 

 pagation was precisely that of exanthemalous typhus, which in 

 tlie jireceding two years had claimed numerous victims in Tunis. 



A^ has been already established in the case of the lattei' disease, 

 there was no contagion in the wards where the sick were isolated 

 and treated; the only cases occulting in the hosi)ital itself were 

 those among the statf of the receiving waid. As with exanthema- 

 tous typhus, the sufferer from recurrent fever is no longer c(nita- 

 gious'when once his clothes have been removed and he has been 

 washed, and thus theauthors were gradually driven totlieconviction 

 that in spite of the failure of other (d)servers to prove that the 

 louse could carry infection by its bite, the louse, and thekmseonly. 

 was the transmitting agent of recurrent fever. Starting with 

 this coiivn-tion they repeated a large niimheiof e\])eriments()i 

 otlier observers and were able to prove to their own satisfaction 

 that neither man nor monkey is capable of receiving the disease 

 through the })ites of lice which liave been fed to the fullest 

 possilrie extent u])on the bodies of patients suffering from it. 

 Some of the monkeys were bitten between two and three hundred 

 times, under various suitable conditions, without result; five men 

 were similarly exi)eriniented with, each of whom was bitten a very 

 large number of times by infected lice under proper conditions, 

 but"" without result. The authors thus found that theii- careful 

 experiments were directly contrary to the conviction acquired 

 from hospital and similar experiences. The next point investi- 

 gated was the behaviour of the spirilla ingested by the lice. The 

 general result of these observations, which appear to have been 

 carried out with extreme care, was tliat the spirilla ingested at first 

 disappear entirely, but reappear about the twelfth day as exceed- 

 ingly minute and active organisms. A larue number of oliserva- 

 tions are recorded, which had for their o1).iect the determination 



