There is an increase in the number of red corpuscles in the blood and also a slight increase in the number of white corpuscles during the period of the administration of the preservative. The intensity of the color of the blood diminishes, however, both in the preservative and in the after period. There is a marked decrease in the number both of red and white corpuscles in the after period. The apparent increase, therefore, in the preservative period is followed by a very considerable decrease in the after period. No conclusion, favorable or unfavorable, can be drawn from this observation regarding the use of the preservative, tho apparently, if there is any effect produced, it should be attributed to a favorable inﬂuence of the preservative in increasing the number of red corpuscles.