In Haasis's (I928) paper on the germinative energy of lots of seed of pitch pine and of other coniferous trees it is stated that a lot of rice seed was included in the experimentation there described, which was carried out at the Laboratory of Plant Physiology of the Johns Hopkins University in I927 and I928. The present paper presents the main results of the experiments with rice there referred to, together with some discussion of relations between time, temperature, and germination percentage. In the preparation of this article we have had critical and bibliographic help from Dr. Thomas I. Edwards, of the School of Hygiene and Public Health, of the Johns Hopkins University. The standard cultures of rice were essentially like the standard cultures of pitch pine seed described by Haasis, and those employed in Edwards's (I933) study of soybean seed were similar in many respects. Each culture regularly contained 50 seeds, taken as a random sample of the lot. After an hour of preliminary soaking, at about 20? C., the seeds were uniformly distributed on agar plates in covered Petri dishes. To the water in which the seeds were to be soaked was added 0.25 g. of Semesan powder for each IOO ml. According to the statement of the manufacturers, this material contained 35 per cent, by weight, of hydroxy-mercuri-chloro-phenol. For the agar plates, the granulated preparation called Bacto-Agar was used, IO g. for each liter of water, and each culture dish contained 20 Ml. of the mixture. A series of tests at temperatures between 8? and 24? included seed samples soaked in distilled water as well as those soaked in antiseptic solution, but there was no indication of any significant difference between the results froni the two soaking treatments. We may regard the antiseptic treatment as without considerable effect on the results of this study, but it was a regular feature of the experimental background. Tests with seed samples that had not received any preliminary soaking at all gave results that were essentially like those secured with soaked seeds, excepting that the time period needed to give any specified germination percentage with a given maintained temperature was somewhat longer when unsoaked seeds were used, as might be expected. When hulls were removed from the seeds before they were distributed on the plates, without preliminary soaking, the results were like those secured when unsoaked seeds were used with hulls still present.