640 



especially if it be spread out in a tiuiform layer immediately upon being taken from 

 the water. 



In a number of plats tbe seed treated in bot water bad been previously soaked sev- 

 eral hours in cold water. The effects of this soaking were as expected ; the smut was 

 fully prevented by a shorter immersion or by treating at a lower temperature than is 

 necessary when dry seed is used. Further experiments will be necessary before this 

 form of tbe hot-water treatment can be recommended. Without doubt previouslj' 

 soaking the seed will greatly shorten the time necessary for the treatment — pexhaps to 

 5 minutes. 



Treating the seed for a short time in waterof a higher temperature was also found to 

 be effective in destroying the smut. It is likely, however, that in treating dry seed 

 at high temperatures there will be danger of leaving a few seeds uuwetted, especially 

 when large quantities are treated at once. There is also danger that the center of the 

 mass of seed will not have time to become heated to the temperature of the water. 



Because of the uncertainty of these modifications of the bot- water treatment, we 

 recommend, as before, the immersion of dry seed 15 minutes at 132.5'^ Fah. * * * 



A comparison of the results here published with those for wheat given in Bulletin 

 12, shows that oats are injured by chemical solutions much more easily than wheat. 

 The effect of hot water is apparently about the same on both. 



Increased yield on treated plats (pp. 120-127). — The comparative yields 

 on forty-seven of the best treated and untreated plats are shown graph- 

 ically in diagrams. It was found that very many of the treated plats 

 gave a yield greatly exceeding that which would result from simply 

 replacing the smutted heads in the untreated plats with sound ones. 



The direct damage in the untreated plats, resulting from part of the heads being 

 smutted, averaged 11.34 per cent. The treated plats gave an average yield 45.27 per 

 cent greater than that of the untreated plats, or nearly four times as great an 

 increase as would be obtained by merely replacing the smutted heads in the untreated 

 plats with sound ones. 



This is in accord with the results of experiments previously recorded 

 by the authors. It has been suggested by the authors and by Jensen 

 that the increased yield is due to the fact that the hot-water treatment 

 causes the seed to germinate better. This, however, " seems entirely 

 inadequate to account for the extra increase observed In our experi- 

 ments, both in 1889 and 1890." Jensen has recently suggested that 

 many plants are weakened by smut which does not reach the head, but 

 smut of this character has not yet been observed. 



Directions for treating the seed (pp. 128-130). — Full directions are 

 given for the treatment of oat seed with hot water and with potassium 

 sulphide. With regard to the former treatment the following sugges- 

 tions are made: 



Provide two large vessels, as two kettles over a fire, or boilers on a cook stove ; the 

 first containing warm water (say 110° to 130°), the second containing scalding water 

 (132.5°). 



The first is for the purpose of warming the seed preparatory to dipping it into the 

 second. Unless this precaution is taken, it will bo difficult to keep the water in the 

 second vessel at a proper temperature. 



The seed which is to be treated must be placed, a half bushel or more at a time, in 

 a closed vessel that will allow free entrance and exit of water on all sides. For this 

 purpose a bushel basket made of heavy wire could be used, within which spread wire 



