that the cases at Stuttgart and at Craponne must have been tended and their linen washed. How was it that no further cases occurred, and that an epidemic was not started? The linen of the case from Munich was poisonous, but not that from the cases at Stuttgart! Must we not also suppose that another factor is necessary to explain the further spread of cases introduced from without? And this local factor was wanting at Craponne and Stuttgart. If a case from Munich caused three at Stuttgart, then the latter ought to produce nine. In places which enjoy immunity from epidemics it is conceivable that sporadic cases may occur, but, the conditions which are necessary for the production of an epidemic being wanting, no further development can take place. The soiled linen appears to me to be infective not because it comes from cases of cholera, but on account of its arrival from a locality where cholera prevails. Perhaps linen is a good vehicle for transmitting the infective material produced in a locality under the necessary circumstances of time and place. Man is the only creature that wears linen, and perhaps he alone spreads cholera, and it is possible that whether he were clothed or naked he would spread it just as much and no more. But, if we accept this doubtful solution of the Gordian knot, still the views of the contagionists on the dejecta of cholera and the soiled linen would not stand on a firmer basis, since we see not only individual cases but actual epidemics arising without the introduction of soiled linen. The infective material which produces cholera may be transmitted at all events in other ways along the paths of human intercourse. The germs of cholera may be brought from a locality to a place where the necessary relations of time and place are not favorable for the epidemic development of cholera, and they may there slumber for a month before they develop. There is every chance for the propagation of cholera in India, and yet cholera only shows itself fitfully in districts lying outside the endemic area. If the intercourse with India be reduced to the least possible, as it was in the last century, yet cholera might still at times visit us.
Finally, I shall ask myself what can be done to ward off cholera? The measures to be adopted will be very different according to the theory adopted. According to the contagionists, the spread of epidemic cholera depends on personal and material intercourse, as well as on conditions of time and space when the germs arrive at certain localities. Moreover, the severity of the epidemic is supposed to depend on the individual susceptibility. If one of these three factors be wanting, an epidemic of cholera can not develop. Preventive measures against cholera may be devised in one of three directions: (1) intercourse; (2) disposition in time and place; (3) individual predisposition. Measures to prevent the spread of cholera by interfering with human intercourse are, for many reasons, impracticable. If we ask ourselves what good has resulted from sanitary cordons, inspection, and quarantine, we are bound to answer, None. All these measures
