VOL. 79, No. 2036

amount of maltose formed at the blue-violet iodineendpoint in different preparations varies greatly. Ina few cases, the iodine color endpoint was reachedwithout any measurable maltose formation. This ob-servation demonstrates, for the first time, that anamylase preparation can be made which in the earlystages of starch digestion yields no reducing groups.This phenomenon is significant to the study of theconstitution of starch.

Incubation of an aqueous liver suspension causes aconsiderable increase in its capacity to form maltose,while the iodine endpoint activity increases onlyslightly. In the centrifugate of such a preparationthe comparative ratio of sugar formation to iodineend-point value is found to have shifted still furtherin favor of the sugar-forming component. Addingthe resuspended residue to the centrifugate causes thelatter to lose the increase in sugar formation observedin centrifuging, the iodine endpoint activity beingpractically unaltered throughout. The hypothesis,that there are two amylases with different character-istic maltose levels at the same iodine color endpoint,and an unstable inhibiting substance specific for thecomponent showing more maltose formation, explainsthe observations here reported.The inhibitor, soluble in fresh liver centrifugate,

can be precipitated by treatment with acetic acid, pH5.2, for 30 to 120 minutes. Resuspended in water,the precipitate can be redissolved by neutralizing, andin either state has a quantitative inhibiting effect onthe formation of maltose from starch by liver prepa-rations.By treating fresh aqueous liver extracts with vari-

ous concentrations of acetone, very stable amylasepreparations have been made which show reproduciblemaltose formation at the iodine color endpoint atdifferent levels, ranging from 3 to 15 mg per 100 mgstarch. The conditions for producing fractions witha low sugar-forming level are very delicate, and haveyet to be completely defined.

It is apparent that the digestion of starch by liveramylase, like that by plant amylase, is performed bytwo different components. Each component splitsstarch molecules in its own fashion, forming the frac-tions which make up the total course of carbohydratebreakdown.The complete procedure and results of this study

will be published in a later paper.The author acknowledges indebtedness to Dr. Ellice

McDonald for his valuable counsel and encouragementthroughout this work.

LEONORE HOLLANDERCANCER RESEARCH LABORATORIES,GRADUATE SCHOOL OF MEDICINE,UNIVERSITY OF PENNSYLVANIA

A CANKER AND GALL DISEASE OFGARDENIAI

A CANKER and gall disease has been observed tooccur on the branches, stems and particularly thecrowns of several varieties of Gardenia grown li

greenhouses in the San Francisco Bay region inl Calilfornia. Infection apparently takes place onlJthrough wounds and most readily where the wouiide(Ipart is near or in contact with the soil. On brancheliand stems not in contaet with the soil the diseasemanifests itself as oblong cankers, frequently with thewoody cylinder exposed at the point of infection andwith the bark surface rough and corrugated. Oiinfected crowns the cankers remain typical for a con-paratively short time, after which they become overgrown with hypertrophied cortical tissue. This hb-pertrophy involves the entire circumference of thlestem, increasing its diameter to twice normal or moreand extending longitudinally one to two inches iiiboth directions from the point of infection, giving theeffect of an oblong gall. This abnormal swellingseems to be correlated with moisture, as it is apparentonly where infected parts are in contact with the soil.In both cankers and galls the cortex is colored bright-yellow a considerable distance in advance of the ill-vading fungus. Pyenidia of the causal organism arefound partially submerged in the cortical tissues sur-rounding the point of infection. Two types of sporesexude in a short tendril from the same pyenidiumn.One, the A type, is hyaline, unicellular, elliptic-fusi-form; mean size 3.4 x 9.7. The other, B type, is hyaline, unicellular, filiform, curved or flexuous; meaiisize 1.4 x 22.2.The two spore types would indicate that the causal

organism belongs in the genus Phomopsis. The funi-gus is readily isolated in pure culture both from sporetendrils and from tissue plantings of diseased parts.Inoculation of twigs and crown of Gardenia withthis organism gave rise to typical cankers and gallsfrom which the fungus was re-isolated and again snie-cessfully caused to infect Gardenia plan-ts.

H. N. HANSENC. EMLEN SCOTT

UNIVERSITY OF CALIFORISIA, BERKELEY1 Contribution from the Division of Plant Pathology,University of California, Berkeley, California.

BOOKS RECEIVEDAnnual Report of the Secretary of the Interior for the

Fiscal Year Ended June 30, 1933. Pp. 329. U. S-Government Printing Office.

MARTIN, THOMAS. Faraday's Diary. Vol. III, May 26,1836 to November 9, 1839. Pp. xii + 466. Vol. IV,November 12, 1839 to June 26, 1847. Pp. xii + 448.Illustrated. G. Bell & Sons, London. £12 12s, forset of seven volumes.

TYSON, LEVERING. Radio and Educationa. Pp. vii + 203.University of Chicago Press. $2.50.

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