214 BACTKKIA IN THE MANUFACTURE OF SUGAR 



it.iin decree of (in.-ici-o-copii-) ac<|iiaintaiiee with the individual nialadi. 

 which they treat. (Mi the other hand, tin- YOUM^ su^ar -trrhiiirist , who will, as 

 a rule, be mainly d>imus of determining the nature of the di.-t-a.se brought 

 under his notice, i> advised to study (I KIKCIINKK'S (1.) u 1 landlmch der 

 Pflanzenkrankheiten " (" Handbook of Plant Diseases "). This work is admirably 

 supplemented by a good and cheap atlas (prepared by O. KIIICH.XKK and II. 

 BOLTSHAUSEX (I.)) of coloured plates showing the chief diseases attacking 

 industrial plants. With the information 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 vegetable 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 nernatode 

 sickness) in a monograph by A. STRUBELL (I.), as also in a useful work by 

 J. VANHA 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 gummosis (Fr. yommose) of the 

 sugar-beet, a complaint first described 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. 



