To the Editor:
—Several criticisms of my letter (The Journal, May 10, p. 1386) on the administration of arsphenamin have appeared and seem to demand the following comments:Dr. Goldenberg (The Journal, May 31, p. 1634) uses only 20 c.c. of distilled water for 0.1 gm. of drug, two thirds of the amount for dilution that was suggested in my letter, and employs about half of the time I mentioned. Dr. Pusey (The Journal, June 14, p. 1786) approves from 20 to 25 c.c. per decigram, and Dr. Nelken (The Journal, June 7, p. 1695) uses a solution as concentrated as 0.6 gm. of the drug in 20 c.c. of water, and gives the dose in from 20 to 30 seconds.No one knows how far concentration of drug and rapidity of administration may be carried without undue risk to the patient, and it is possible that the limits Dr.