MR. MADAN in his amusing letter last week (p. 533) raises a point which has doubtless often caused the comments of teachers. I think “a partical of reasoning” at least can be adduced in favour of “radical.” In this paradoxical world it is not surprising to find that “radical” is the “conservative” and “constitutional” spelling, and that “radicle” is a radical alteration in a centenarian word. For next year will be the hundredth anniversary of what was, if I am not mistaken, the first use of the word by Guyton de Morveau. It seems to have long retained its French spelling, and I think it would be a pity to alter one which thus recalls to the memory a host of great names, and perhaps more than any other single word in chemistry suggests the international brotherhood of scientific men. Of course Mr. Madan's protest has force from the grammatical point of view; it may also be urged that “radicle” is English for the French “radical.” But from the chemical standpoint surely the “radical” is as much a “stem” as a “root”? For instance toluene is either C6H5(CH3), or CH3(C6H5), and it would be arbitrary to select from a very limited number of reactions the “root” in prussic acid, H.CN, C.NH, or N.CH. Many chemists prefer “grouping,” a safer word often used by Prof. Odling in his lectures.