June, 1020] PATHOLOGY 391 



2688. Mann, Harold H., and S. D. Na<;im:kkak. Notes on the "ring disease" of potato. 

 Agric. Jour. India 14:3<S,X 394. 1919. The ring disease, a bacterial wilt (organism Dot 

 named), of the potato is the greatest, enemy of the potato in the potato trad, of the Bombay 

 Presidency. The bacteria produce a sudden wilting of the plaid and the diseased tubers 

 •how a brown ring in the vascular tissues, commencing, as a rule, near the point of attach- 

 ment of the tuber to the plant, but Btwftding around the whole tuber. The infection occurs 

 in the lower part of the stem in which the ring can usually be seen. Often 20 to 80 per cent 

 of the plants in a plot die of the disease. Experiments conducted show that the disease is 

 extremely infectious and may be spread even by the knife used in cutting the sets. The 

 organism usually is conveyed from crop to crop through the seed and the soil. Infestation 

 in the soil may be reduced by 75 per cent if the soil is allowed to lie idle for 2J months and 

 entirely disappears after 5 or 6 months. Disease free seed is the best means of eradicating 

 this fatal disease. — F. M. Schertz. 



2689. Massa, C. Una teleforacea dannosa al leccio (Stereum gausapatum Fr.). [Stereum 

 gausapatum injurious to holm-oak.) Ann. R. 1st. Sup. For. Naz. Firenze 3: 1-31. 2 pi., 11 

 Jig. 1918. — Fruiting bodies of the fungus have been observed in the vicinity of Florence on 

 the trunks and branches of holm-oaks planted in hedges, which frequently become weak- 

 ened by excessive and irregular pruning. The organism is considered a facultative para- 

 site, occurring commonly as a saprophyte on fallen branches and on stakes and supports for 

 hedges made from the wood of holm-oak. The injury caused to the host is serious, resulting 

 in death if the plant is in a weakened condition. Examination of an affected trunk shows a 

 characteristic alteration of the wood. Detailed study has been made of the organism and its 

 relation to dead and living tissues of the host. It will be necessary to secure further con- 

 firmatory data and to obtain the characteristic pathological symptoms of the disease on 

 healthy trees in order to prove conclusively that they are caused by the mycelium of the 

 fungus. Suggestions for control include protection of wounds with tar, care to avoid exces- 

 sive pruning, use of healthy young trees in starting hedges, and of sound wood treated to 

 protect it from infection for posts and supports, and the removal of dead wood and diseased 

 trees. — E. K. Cash. 



2690. Matouschek. [Rev. of: Gertz, O. Makrokemiska agghviteprof a blad. (Macro- 

 chemical tests of leaves.) Bot. Not. 1917:1-35.] Zeitschr. Pflanzenkrankh. 29:51-52. 

 1919. — The analysis of calico or albinism in leaves showed correlation between positive albumin 

 reaction and increase in green colour of leaves. The white portions showed no reaction. 

 The reaction is due to the amount of chlorophyll contents increasing the albumin. In barley 

 strains discussed by Nilsson-Ehle, which showed presence or absence of chlorophyll, the 

 reaction was positive in the former, but negative in the latter. The investigations agree 

 largely with the work of Lakon [Biochem. Zeitschr. 78. 1916.] on the albumin contents of 

 albino leaves. — H. T. Gussow. 



2691. Matouschek. [Rev. of: Heyde, G. v. d. Frostwirkung an Buxus sempervirens 

 Handworthii. (Effects of frost on Buxus sempervirens Handworthii.) Mitteil. Deutsch. 

 Dendrol. Ges. 1917: 235-236.] Zeitschr. Pflanzenkrankh. 29: 54. 1919.— Early in 1917 

 there occurred in Dortmund, low temperatures ranging down to — 16*C. The leaves of the 

 above mentioned shrub were swollen to a thickness of 4.7 mm. The ice in the interior of the 

 leaf was easily removed together with the lower leaf surface. Exposed to +10°C. this lower 

 epidermis would easily peel away from the ice skeleton, leaving a clear impression of the leaf 

 nervature behind. — H. T. Gussow. 



2692. Matouschek. [Rev. of: Kuster, Ernst. Ursachen und Symptome der Unter- 

 ernahrung bei den Pflanzen. (Causes and symptoms of malnutrition in plants.) Naturwiss- 

 enschaften 5:665-669. 1917.] Zeitschr. Pflanzenkrankh. 29: 52-53. 1919.— Lack of nutri- 

 tive salts or carbon dioxid cause malnutrition in plants. At times these substances may be 

 available, but for some reason or other the plant is not able to make use thereof. Such 

 reasons include: injury or parasitic attacks of the root system, anomalies in metabolism, 



