f 



580 Typhus Fever 



to feed upon the blood of an infected monkey, and then upon a 

 healthy monkey. The healthy monkey contracted typhus fever. 

 In the same year, and working independently, Goldberger and 

 Anderson* made two attempts ot infect healthy monkeys by per- 

 mitting lice fed upon cases of t5^hus fever in men, to bite them. 

 They had partial success — the monkeys became diseased but no 

 immunity tests were made for confirmation of the nature of the 

 disease. 



Ricketts and Wilder f working in Mexico succeeded in transmitting 

 typhus fever from man to monkeys by means of lice — Pediculus 

 vestimenti. They also succeeded in transmitting the disease to a 

 monkey by scarifying its skin and applying the abdominal contents 

 of some infected lice, so that it was proved by them that the cause 

 of infection was in the lice. In the course of these experiments 

 Ricketts contracted t}rphus fever and unfortunately died. Later 

 NicoUe and ConseUJ also succeeded in infecting a monkey by the 

 bites of infected Uce. 



Wilder § further found that the infectious agent passes from the 

 infected hce to a second generation of insects, as does the spiro- 

 chaeta of relapsing fever to subsequent generations of ornithodorus 

 ticks. Wilder failed in experiments directed toward infecting 

 monkeys by fleas or bed-bugs. 



In the experiments recorded by Wilder, the transmission of typhus 

 fever to monkeys, by lice, was successful in 7 out of 10 attempts. 

 It required 17 hce to infect a monkey. In one case a monkey 

 seemed to be immunized by being bitten by very young lice. 



Goldberger and Anderson|| also experimented with the head 

 louse Pediculus capitis and succeeded in showing that it too takes 

 up the typhus fever virus and may pass it on from human being to 

 monkey, and hence probably from man to man. 



A description of the lice will be found in the chapter upon "Re- 

 lapsing Fever." 



Bacillus Typhi-exanthematicus (Platz) 



Ricketts and Wilder had observed a small bacillus both in the blood of some of 

 their patients and in the intestinal contents of some of the lice that they investi- 

 gated, but saw no reason for believing it to be the cause of the disease. What may 

 be the same organism was rediscovered by PI itz ("Jour. Amer. Med. Asso.," 1914, 

 J ixn, p. 1556) in the blood of a series of cases(of the variety of typhus fever called 

 Brill|s disease. It is too early to accept this bacillus as the cause of the disease, 

 but it is certainly worthy of careful consideration. According to Platz it b 

 characterized as follows: 



Morphology. — It is a small straight, short, coccoid pleomorphus bacillus measur- 

 ing 0.9-1.93 jti in length by 0.3-0.6 m in breadth. Polar granules can be demon- 

 strated by appropriate staining. It has no capsule. It is not motile and has no 

 flagellae. It forms no spores. 



* "Public Health Reports," 1910, xxv. 



t "Jour. Amer. Med. Asso.," 1910, liv, 1304. 



X "Compt.-rendu. de I'Acad. des Sciences de Paris," 1911, Cllii, 1522. 



§ "Journal of Infectious Diseases," 1911, ixi. 



II "Public Health Reports," 1912, xxvii. 



