Plague

lity and the danger of a world-epidemic; a danger which has existed for some

ease, caused solely by Bacillus pestis, a bacterial organism. The dis

ue arise. In California the ground squirrel (Citellus beecheyi), a rodent closely related to the marmots of Asia, plays a similar r?le. Of the Asian marmots, the ta

t is perhaps wiser and safer to consider the disease infectious, inoculable and contagious in the common medical meaning of these terms. While it is usually c

of bacilli, either the flesh of plague-infected animals or fowls, or food superficially co

been disputed and denied. However, the recent occurrence of plague in a cat in Manila, in my own experience, observed with me and carefully worked out by Dr.

teriologic observations of Dr. Sch?bl and in m

e also use terms descriptive of the severity and course of the cases. Thus we describe certain cases as ambulant, abortive, larval and fulminant. In the rat the evidences of plague are less striking in life than they are at the post-mortem table. Indeed pl

s to leave room for further experimentation. At present it is believed that the flea deposits plague bacilli, at the time of biting, upon the skin, by ejecting the contents of its rectum and by regurgitation of its

l, P. H. and M. H. S., for numerous facts utilized in the preparation of this article. The particular contributors whose valuable chapters have been drawn upon for

perimentally shown that the average capacity of a flea's stomach is about one-half of a cubic millimetre and that thousands of plague bacilli may be ingested by the flea during the biting of a plague-diseased rat; that the plague bacilli

the most common human flea (Pulex irritans) is frequently found upon rats, the flea, generally speaking, being much le

ries generally. It bites both rat and man. Ceratophyllus fasciatus, the common rat flea of Great Britain and the United States, also bites both rat and man.

fest rats, and fleas of other genera are found upon m

gainst fleas must be made upon all fleas and not upon a single variety. In this connection the possibilities of the co

aries and the fly and the cockroach as possible food contaminators. Indeed, laboratory experim

frequent excursions from rat-host to human-host, his taste for blood from either host, his enormous activity and his ability to jump. After a searching inquiry into the plague quest

ncy of fleas. While these conclusions are probably true-and therefore of the utmost importance from the standpoint

om their principal avenues of travel in cities (the sewers), into houses and buildings. (c) By effect upon the plague germ, Bacillus pestis. The resistance of this organism is very variable, sunlight and drying being its greatest enemies, while darkness and dampness are its chief all

revalence of rat fleas. During the periods when rat fleas are absent or least prevalent, the disease is perpetuated in the form

to attenuate or to intensify cultures of plague bacilli permanently in laboratory experiments with animals. If it is true that plague epidemics are often marked by a preponderance of mild cases in the early days and a gradual subsidence of intensity of the cases as the epidemics wane, we probabl

nea-pigs.[2] If his observations are correct (and they seem to correspond with the findings of other observers), the oft-recorded occurrence of a preponderance of mild cases of plague in the early days of an epidemic and the gradual subsidence in intensity of the disease as the epidemic approaches its close will

ence, June 1907, No. 3. Frequent reference has been made to these studies

re us, we are in position to approach the problem of prevention intelligently, and in the case

revention thus: Without fleas, without rats, or without human plag

man plague cases, and the exclusion from them of all suctorial parasi

f plague occasionally occurs in epidemics of great fatality, as, f

led by the work of the Americans, Strong, Teagu

plague pneumonias are the starting points of epidemics of pneumonic plague, i.e., of cases of primary plague pneumonia, the

low temperature; conditions most unfavorable to evaporation and ventilation. Under these conditions t

ermore, that in the absence of original cases of bubonic and septic?mic plague, with secondary plague pneumonias whi

the conveyance of respiratory pla