December 22, 1910] 



NATURE 



237 



ORIEXTAL OK BUBONIC PLAGUE. 



PLAGUE is an acute infective disease, an infectious 

 fever, attacking man and some of the lower 

 animals, and attended with a considerable mortality. 

 The svmptoms in man develop within a few days of 

 infection, and consist of fever, headache, giddiness, 

 weakness, with staggering gaii, great prostration, and 

 delirium. In 75 per cent, of the cases the lymphatic 

 glands in the groin, armpit, and other regions are 

 inflamed, infiltrated, and much enlarged, constituting 

 the "buboes," hence the name "bubonic plague" 

 frequently given 10 the disease.^ In the remaining 

 cases, the lungs may be primarily attacked, the "pneu- 

 monic " form, or a severe blood infection may develop, 

 the " septicaemic " variety; in both of these buboes are 

 absent, or are a late development if the patient lives. 

 Occasionally an eruption of pustules or carbuncles 

 appears on the skin, a phenomenon frequently men- 

 tioned bv the older writers, and abscesses may form 

 in the buboes. The bubonic form is hardly infectious 

 or even contagious, but the pneumonic variety is 

 highly infectious, owing to the presence of large 

 numbers of the infective agent, the plague bacillus, in 

 the expectoration from which it is readily disseminated 

 in the air. In some instances the patients do not 

 appear particularly ill, and are able to go about, 

 though such cases are liable to sudden death from 

 heart failure. 



The micro-organism of plague was discovered inde- 

 pendently by Kitasato and by Yersin in 1894. It is a 

 stumpv. rod-shaped organism or "bacillus," having 

 rounded ends, and measuring as a rule about 1/8000 

 inch in length, and i / 16000 inch in breadth, but longer 

 forms occur. In smears made at an early stage of 

 the disease from the buboes, expectoration or blood 

 respectively in the three varieties, the bacillus is pre- 

 sent in enormous numbers, and if the films are stained 

 with an aniline dye, such as fuchsia, it tends to stain 

 deeplv at the ends ("polar staining "), the centre being 

 hardly stained at all (see Figs, i and 2) ; this is a very 

 characteristic appearance. In older lesions peculiar, 

 large, rounded or ovoid "involution" forms of the 

 bacillus are met with. The organism can be readily 

 cultivated in various media in the laboratory ; it is 

 non-motile, and does not spore, and is readily destroyed 

 by heat (60° to 65° C. for ten to fifteen minutes), and 

 by disinfectants. The plague bacillus is pathogenic 

 for a number of animals, in addition to man — the rat, 

 mouse, guinea-pig, rabbit, hare, ferret, cat, monkey, 

 &c. In the United States the ground squirrels are 

 attaclied. 



A remarkable feature which has characterised 

 plague from the earliest times is the alternation of 

 periods of widespread prevalence, "pandemics," with 

 periods of quiescence and complete intermission. 

 Thus, in the fourteenth century, in the course of three 

 years, plague decimated the whole of Europe, with an 

 estimated destruction of one- fourth of the population, 

 appearing in England as the black death.- In the 

 fifteenth, sixteenth, and se%-enteenth centuries there 

 were frequent outbreaks in Europe, Asia, and Africa, 

 more or less limited in extent, culminating in England 

 in the great plague of London, with 97,^06 burials in 

 1665, of which 68,596 were attributed to plague, 

 whereas in the five vears preceding and succeeding 

 this terrible visitation the normal number of burials 

 in London ranged from about 15,000 to 20,000. 

 Plague then rapidlv disappeared from western Europe, 

 so that by the end of the seventeenth centurv it was 

 practically extinct, and save for isolated outbreaks 

 (e.g. at Slarseilles and Toulon in 1720) occurred only 



1 Although this is the rule. Prof. Simpson oo'nt-; out that in Accra, West 

 -Africa, 50 per cent, of the cases were of the pneumonic variety. 



2 I am indebted to Prof. .Simpson's " Treatise on Plague " for these and 

 other historical details. 



NO. 2147, VOL. 85] 



in Turkey, the Levant, Egypt, and Asia Minor. Thus 

 plague was practically unknown to the present genera- 

 tion until 1894, when it reappeared in epidemic form, 

 this time in Hong Kong. There have always been 

 localities in which plague has been "endemic," i.e. 

 continuously prevalent, for example, on the Persian 

 Gulf, in Asia Minor, and in Yunnan, a province of 

 China bordering on Burmah and Tibet. According to 

 Prof. Simpson, plague travelled from Yunnan by the 

 overland trade routes to Canton, thence by river to 

 Hong Kong ; from Hong Kong the disease was sea- 



FlG. I. — Smear from bubo snowing^ Jarge numbers of 

 plague bacilli. X i30o. 



borne to India, where it certainly appeared in 1896, 

 and since then has similarly been carried all over the 

 world. The agent by which the disease has been so 

 widelv disseminated is the rat, infection from maVi to 

 man being almost negligible, the rat fleas being- the 

 intermediaries betw^een the rat and man, and 

 mechanically conveying the infection — the plague 

 bacilli — frorn rat to rat, and from rat to man (vide an 

 article by Dr. Petrie in Nature, November 3, p. 15). 

 For combating the spread of plague, the destruction 



Fig. 2. — Smear froii. fected Ferret (from 



Suffolk), showing typical bi-polar staining plague 

 bacilli. X 1200. 



of rats is therefore an important measure. While it 

 seems hopeless to effect complete destruction of these 

 rodents, a great deal can be done to lessen their 

 numbers, and the survivors will probably be less likely 

 to be infected. The destruction of rats may be carried 

 out bv systematic trapping, ferreting, and poisoning, 

 but anvone who has had to deal with rats is aware 

 how "cute" they are, and the most tempting morsels 

 will often fail to attract them to trap or poison. Hand- 

 ling the material or trap is sufficient to rouse their 

 suspicion, and the "taint" of man, if present, must 

 be destroyed by flaming or disguised by the use of 



