278 BACTERIA IN THE MANUFACTURE OF SUGAR. 



a certain degree of (macroscopic) acquaintance with the individual 

 maladies of which they treat. On the other hand, the young 

 sugar-technicist, who will, as a rule, be mainly desirous of deter- 

 mining the nature of the disease brought under his notice, is 

 advised to study 0. KIRCHNER'S (I.) " Handbuch der Pflanzen- 

 krankheiten" ("Handbook of Plant Diseases"). This work is 

 admirably supplemented by a good and cheap atlas (prepared by 

 0. KIRCHNER and H. BOLTSHAUSEN (I.) ) of coloured plates showing 

 the chief diseases attacking industrial plants. With the informa- 

 tion thus gained, the learner will then be able to resort with 

 advantage to the two first-named standard works. A brief review 

 of the most important diseases set up in the sugar-beet by veget- 

 able or animal parasites has been written by A. STIFT (I. and 

 II.), and particular attention is devoted to Heterodera Schachtii 

 (the cause of the so-called nematode sickness) in a monograph 

 by A. STRUBELL (I.), as also in a useful work by J. YANHA and 

 J. STOKLASA (I.). Investigations on the influence of these worms 

 on the cellular activity of the beet, and on the resulting chemical 

 changes thereby induced, were made by J. STOKLASA (I.), and may 

 now be mentioned. At present we will merely refer briefly to the 

 gmnmosis (Fr. gommose) of the sugar-beet, a complaint first de- 

 scribed by SORAUER (II.). The symptoms of this disease are : 

 extravasation of small drops of a gummy fluid from the unbroken 

 surface, and a gradual blackening of the vascular bundles and 

 parenchyma of the beet, from the tip of the root upwards. It is 

 still uncertain whether the bacteria so abundant in this gum 

 should be regarded as the actual cause of the disease or merely as 

 harmless saprophytes. 



