COMMUNICABILITY— DIAGNOSIS 



1557 



ulcerations, as well as on to ordinary ulcers. In Nuttall's classical 

 work on the role of insects as carriers of parasitic diseases several 

 authors are quoted (Alibert, Hoish, Cadet, Wilson) who believe that 

 the infection may be conveyed from one individual to another by 

 flies. Wilson states that this belief prevails among the natives of 

 the West Indies. 



One of us made some experiments to prove that flies are instru- 

 mental in the dissemination of the disease. A number of flies were 

 fed on scrapings from slightly ulcerated frambcetic papules. The 

 flies {Musca domestica and allied species), before feeding on the 

 frambcetic material, were examined. The examination showed 

 that they did not harbour any treponemata, either on their mouth 

 organs or on their legs. On examination after feeding, the majority 

 presented coarse spirochaetes, and a few of them also T. pertenue. 

 In another experiment flies fed on yaws material were placed on 

 scarified spots over the eyebrows of several monkeys, and kept 

 there for two hours by means of strips of gauze smeared with 

 collodion at their margins. One of the monkeys became infected. 

 Sambon considers that a fly of the genus Hippelates plays a very 

 important role in the dissemination of the disease in the West Indies. 



Modder some years ago suggested that Ixodes hovis — i.e., Margaropus 

 annulaius var. australis — or some of the Argasidae might be the transmitting 

 agent. Bahr has suggested that the causative treponema may be transmitted 

 by some blood-sucking insect whose range is definitely limited by the character 

 of the vegetation or by climatic factors. According to certain authorities 

 yaws may be communicated by means of food. R. P. Greggio states that 

 natives of some Congo tribes suffering from yaws place inside the manioc 

 they are selling portions of crusts removed from their own yaws lesions, in 

 the belief that in this way the disease will leave them, will ' emigrate ' to 

 the buyers, who will become infected by eating the manioc. 



Diagnosis. — In countries where the disease is endemic the diag- 

 nosis is generally easy, the large framboesiform nodules, capped with 

 thick yellow crusts, being typical. By some observers the disease 

 has been confused with verruga peruviana and with syphilis. 



Verruga Peruviana. — ^This disease is strictly limited to certain 

 valleys of the Andes at an elevation of from 3,000 to 10,000 feet. 

 Its eruptive elements, unlike those of framboesia, frequently attack 

 the various mucosae, and bleed with great facility. The micro- 

 scopical examination for spirochaetes is negative. 



Syphilis. — ^By some authors framboesia has been looked upon as 

 a form of syphilis. The results of experimental investigations of 

 yaws and syphilis prove conclusively that the two diseases are 

 distinct, inasmuch as (i) patients suffering from syphilis may 

 contract yaws, and patients suffering from yaws may contract 

 syphilis; (2) monkeys successfully inoculated with yaws do not 

 acquire any immunity against syphilis; (3) mercury has practically 

 no action on framboesia. 



Syphilis has a world-wide distribution; framboesia, on the other 

 hand, is restricted to certain parts of the tropics. Framboesia is 

 extremely common in Ceylon, extremely rare in India. Syphilis is 



