382 - BOTANICAL GAZETTE [NOVEMBER 
he will discover, in the very careful removal of air from the tissues before 
imbedding, the numerous accurately graded solutions of celloidin (2, 4, 6, 
8, etc., per cent.), the repeated heating and rapid cooling of the objects 
during the process of infiltration, the thickening of the final matrix by the 
addition of chips of celloidin and the use of heat (instead of the usual 
process of evaporation), the hardening by means of chloroform followed 
by STRASBURGER’s solution of equal parts of alcohol and glycerin, the 
method of attaching the objects to the microtome, etc., etc., features of 
greater or less novelty in celloidin technique. It is scarcely necessary to 
discuss the misconception on the part of Dr. CHAMBERLAIN, by which he 
supposes Mr. PLowMaN to claim originality in the matter of using celloidin 
as an imbedding medium. The reference to previous incomplete accounts 
was perhaps unfortunate, but was due to the fact that Mr. C. H. MILLER, 
an assistant in the Anatomical Department of the University of Chicago 
had described imperfectly the celloidin method at present under discussion 
as derived from Prof. R. R. BENSLEY, a former colleague of the present 
writer. In his chapter on celloidin technique, Dr. CHAMBERLAIN too makes 
reference to his indebtedness to Mr. W. B. Mac Catyum, a former student 
of the Ontario Agricultural College, an institution into which the present 
writer’s celloidin method had certainly been introduced. The writer is glad 
to accept Dr. CHAMBERLAIN’S statement, in a letter to Mr. PLOWMAN, that 
he owes nothing to Dr. MacCattum. The mention of possible prior 
publication arising out of the wide informal diffusion of the method was 
not introduced out of any desire to establish priority, but for the purpose 
of obviating just such well meant criticisms as that of Dr. CHAMBERLAIN. 
The excuse for publishing the method is the fact that it gives results which 
excel those obtained by any other process known to the writer.— 
JEFFREY, Phanerogamic Laboratories of Harvard U: niversity. 
E. C. 
THE correction to which Professor JEFFREY refers in his reply was bas 
* - : : r cent. 
used, comes in tablets accompanied by directions stating that a 2 pe 
Solution may be made by adding to a tablet a sufficient quan™ tet 
alcohol to make the whole weigh 20008". For a 4 per cent. solution @ 
tablet could be added, and *o on. The chloroform method 
celloidin after infiltration was described by VIALLANES in 1883 
Vhist. et le dével. des insects, p. 129; also Revue scientifique 3t° 
(Rech. sur 
684-687- 
