ON AN IMPROVED METHOD OF CULTIVATING 

 MICRO-ORGANISMS ON POTATOES. 



By Dr. Oscar Katz. 



(With two Figures in Wood-cut). 



la the first number of the first volume of the " Centralblatt 

 fiir Bacteriologie und Parasitenkunde," edited by Leuckart, 

 Loeffler, and Uhlworra, Jena (Gustav Fischer), 1887, pp. 26-27, 

 Dr. E. Esmarch writes on the " Preparation of the potato as a 

 culture-medium for micro-organisms." He calls attention to the 

 universally recognised value of the boiled potato as a culture-soil 

 for most vegetable micro-organisms, for the identification of some 

 of which, especially the bacillus of typhoid fever (Eberth-Gaff"ky), 

 it is, so far as known, an indispensable and the only reliable 

 medium. 



The hitherto customary processes of preparing potatoes for this 

 purpose are, as Esmai'ch rightly states, far from being satisfactory. 

 He, therefore, proposes the following method. One or more small 

 glass-capsules, of the appearance of the usual damp chambers for 

 cultivating fungi, are sterilised by dry heat. A potato is then- 

 peeled by means of a common kitchen-knife, and, after having 

 been rinsed under the water-tap, divided by the same knife into 

 slices about 1 cm. thick, which are next adapted to the diameter of 

 the glass-dishes and placed in the same. These potato-slices 

 prepared in the above manner, are then boiled by steam in the 

 steam-steriliser for from | to 1 hour, and are shortly afterwards 

 ready for use. 



This process in the preparation of potatoes, and their storage in 

 small glass dishes with over-lapping lids is undoubtedly far 

 superior to the old mode of px'eparation and preservation. 



