16 3 



taxonomlc criterion would mean little if the findings of 

 Mailman (1930) concerning the common antigenicity of 

 Brucella , Pasteurella , and Pfeifferella are correct. 

 Although originally named Bacterium tularense "by McCoy 

 and Chapin, more recent classifications have placed the 

 organism in the genus Pasteurella "because of its similar- 

 ities with other members of the genus , especially Pas - 

 teurella pestis . These organisms agree to a large extent 

 in pathogenicity, pathologic manifestations, morphology, 

 fermentation reactions, selective affinity for rodent and 

 human hosts, and in insect transmission. The tularaemia 

 organism differs from other members of the genus in the 

 difficulty in growing it on ordinary "bacteriologic media. 

 Inasmuch as we have arbitrarily followed the systematics 

 of the Bergey Manual, we have used the name Pasteurella 

 tularensis for the sake of consistency. 



Insects concerned: The squirrel flea, Ceratophyllus 

 acutus; the deer fly, Chrysops discalis ; the ra"b"bit louse, 

 Haemodipsus ventricosus ; the mouse louse, Polyplax serra - 

 tus ; the "bedhug, Cimex lectularius ; the fleas, Ctenophthal - 

 mus pollex , C. assimilis , and C. oriental is ; flies, Tahanus 

 autumnalis ; T. agrestis , T. "bromius , T. erheri, T. flavo- 

 guttatus , T. solstitialis , T. peculiaris , T. karybenthinus , 

 T. turkestanus , T. septentrionalis , T. rupestris , Chrysops 

 noctifer, C . relictus , Chrysozona turkestanica , Simulium 

 decorum katmai , Neohaematop inus laevius cuius , Stomoxys 

 calci trans , Spilopsyllus cuniculi , Cediopsylla simplex ; 

 mites of the family Gamasidae; the ticks, Dermacentor 

 andersoni , D. alhip ictus , D. occidentalis , D. variabilis , 

 D. parumapertus ( marginatus ) , D. silvarum , Haemaphysalis 

 leporis-palustris' ; Ixodes ricinus californicus ; Ornitho - 

 doros turicata , 0. parkeri , 0. hermsi , 0. lahorensis, 

 Rhipicephalus sanguineus ; Ambly omnia americanum ; mosquitoes 

 A^des nearcticus , A. vexans , A. dorsalis, A. stimulans , 

 A. canadensis , A. aegypti , A. caspius , Theohaldia incidens , 

 Culex tarsalis , C. apicalis , and Anopheles hyrcanus . 



In 1911 McCoy described a plague -like disease of ground 

 squirrels ( Citellus "beecheyi ) of California. The follow- 

 ing year McCoy and Chapin (1912) descrihed " Bacterium 

 tularense " as the causative agent. The disease was later 

 named "tularemia" "by Francis. During his original inves- 

 tigations McCoy (1911) found it possible to reproduce the 

 infection in guinea pigs "by the subcutaneous inoculation 

 of crushed squirrel fleas ( Ceratophyllus acutus) which had 

 "been removed from recently dead rodents. Ten years later, 

 Francis and Mayne (1921) reported experimental transmission 



