The purpose of this investigation is to determine in as definite a way as possible whether or not manganese has any. important function in plant economy. The aim of this paper is to describe in a brief way some of the observations and results obtained thus far in this investigation. The method of attack has been the preparation of plant nutrient compounds and quartz sand free from manganese and the growing of plants in different portions of water cultures or sand cultures to which manganese was

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... added or from which it was excluded. The plants were grown until they approached maturity. The green weights were determined a t the time the plants were harvested and the dry weights a t a later time. Chemical analyses were made of the plants grown under the two different conditions with respect to manganese. The work has been done a t the Kentucky Agricultural Experiment Station with the exception of last year during which time it was conducted in the laboratories of the Department of Soil Technology at Cornell University. Further work on this subject is now in progress a t the Kentucky Agricultural Experiment Station. During the last 20 years considerable attention has been given by investigators interested in plant nutrition and soil fertility to the occurrence, distribution and probable function of manganese in its relation to agriculture. The writer is aware of as many as 150 investigations pertaining in one way or another to this subject. In a review of this literature he was inclined to divide it into two classes. One class would include investigations the object of which was to determine whether or not an application of a manganese compound to the soil will increase the yield of a crop grown thereafter. The other class of investigations would include those in which i t has been sought to determine whether or not manganese is an essential element in plant economy. While a few of the investigations included in the fertilizer class have afforded some indication of an economic relation existing between manganese and agriculture they do not afford sufficient evidence to answer the question: Is manganese a necessary element in plant growth?