lodged on their surface as to give them a dark color, but other grains which show no difference in color to the naked eye may still contain a sufficient number of spores to produce a smutty crop if seed treatment is not practised.

"When living smut spores are introduced into the soil with the seed wheat, or exist in the soil in which smut-free wheat is sown, a certain percentage of the wheat plants are likely to become infected. The smut spore germinates and produces first a stage of the smut plant in the soil. This first stage never infects a young seedling direct, but gives rise to secondary spores, or sporida, from which infection threads may arise and penetrate the shoot of a young seedling and reach the growing point. Here the fungus threads keep pace with the growth of the plant and reach maturity at or slightly before harvest-time.

"Since this disease is caused by an internal parasite, it is natural to expect certain responses to its presence. It should be noted first that the smut fungus is living at the expense of its host plant, the wheat, and its effect on the host may be summarized as follows: The consumption of food, the destruction of food in the sporulating process, and the stimulating or retarding effect on normal physiological processes.

"Badly smutted plants remain in many cases under-size and produce fewer and smaller heads. In the Fife and Bluestem varieties the infected heads previous to maturity exhibit a darker green color, and remain green longer than the normal heads. In some varieties the infected heads stand erect, when normal ones begin to droop as a result of the increasing weight of the ripening grain.

"A crop may become infected with smut in a number of different ways. Smut was originally introduced with the seed, and many farmers are still planting it every season with their seed wheat. Wheat taken from a smutty crop will have countless numbers of loose spores adhering to the grains, also a certain number of unbroken smut balls. These are always a source of danger, even when the seed is treated with fungicides before sowing.

"There are also chances for the infection of a crop if absolutely smut-free seed is employed. First, soil infection from a previous smutty crop; 

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