] 68 Scientific Proceedings, Royal Diihlin Society^ 



Writing in 1877, A. Fischer de Waldlieim (8) had, without assigning 

 reasons in detail, placed T. Scabies in the genus Sorospormm as *S. Scabies, 

 retaining it amongst the JJstilaginece. Saccardo adopts this view, as did 



It is, I think, evident that mycologists generally accepted the views 

 expressed by Berkeley, who had, as the quotations I have made show, not 

 found time to give much attention to the disease, and relied mainly on 

 Martius's work, though he clearly regarded the fungus as a Hyphomycete. 



Martius (9) wrote in 1842 his article, Bie Kavtoffel-Epidemie. The 

 article deals in detail with two potato troubles — " Stockfaule," due to 

 Fmisporium Soiani, and suggestive of Fusarium dry-rot of to-day, and 

 " Kartofiel-raude " or scab, the subject of this paper. Martius gives an 

 excellent account of the early stages and external appearance of the scab, and 

 of the injurious effect of the disease on the tubers. The tubers, he states, 

 become unsightly, in pronounced cases have a disagreeable taste, often keep 

 badly in store, and as seed-tubers may fail to sprout, or give shoots which are 

 weak and in the end fall off'. Had his valuable article been translated, 

 digested, and more generally acted on, the benefit to the potato-crop of 

 Britain would have been great. His explanation of the origin of the spore- 

 balls is vitiated by his belief in spontaneous generation. He fully appreciates 

 the important influence of predisposing causes, but states that, owing to 

 unfavourable conditions, the organic juice or sap of the tuber undergoes 

 degeneration, and this so altered juice becomes converted into an "Urpilz" — 

 hisProtomyces — from which the "grains" (spore-balls) arise. He is, he says, 

 further gradually coming to the conclusion that the view that disease is 

 transmitted by means of a myasmic effluvium from a diseased to a healthy 

 organism, is untenable, that a solid body is necessary for infecting purposes, 

 thougli in such a case as scab the low organism responsible can, he thinks, 

 arise cle novo. The first account of the scab fungus is, however, given by 

 Wallroth (10) in Linncea (vol. xvi., 1842). Wallroth states he has long 

 known the disease which was then so frequently mentioned in agricultural 

 papers, and he gives the following diagnosis : — 



" Eri/sibe subterranea, a. Ttiberum Soiani ttiberosi. Sporis subrotundis 

 maximis obscure cellulosis tenuissimis, primum flavicantibus dein fusco- 

 virescentibus sub summa tuberum subterranearum vegetorum epidermide 

 livescente macularl dein coUiculosa lacero-fissa grumulos ovato-subrotuudos 

 hemisphsericos immerses polysporos iisque effoetis scrobiculos superficiales 

 nudos prsBstautibus." 



Martius saw Wallroth's preparations and description, and agreed with 

 him as to the nature of the organism. Martius transfers the fungus, however, 

 to Pruioijii/ces Tuberum Soiani Tuberosi, and gives an amended diagnosis of it in 



