1892.] The Tendrils of Passiflora caerulea. 207 
its development through all stages of growth from the time of 
its appearance as an axillary papilla till it passed out of the 
sensitive stage. During the latter periods of growth sections 
could easily be made withjthe aid of pith and a common hand 
clamp and the collodion embedding method,’ while in the 
younger stages a modification of the paraffin methods given 
y Moll, Campbell and Andrews in the BOTANICAL GAZETTE® 
was found to be more satisfactory. 
The greatest difficulty, however, was experienced in fixing 
and hardening the material. The whole organ is ina state 
of extreme tension and the contact of any reagent on the sen- 
_Sitive concave surface will, unless it has sufficient strength and 
Penetrative power to kill and fix the protoplasmic body in- 
stantly, cause the tendril to roll up in a helix, and the form of 
the wall and contents of the motile cells would be much dis- 
torted. A wide range of reagents was tried with but partial 
Success inany case. Alcohol in strengths varying from 1 per 
cent. to 96 per cent. was found to be useless, as also corrosive 
sublimate. Potassium nitrate was found to give the best re- 
sults in a 4 per cent. solution, but caused the organ to form 
an open helix. Chromic acid distorted the protoplastic struc- 
ture besides rendering the sections difficult to stain. Schulze’s 
chrom-acetic-osmic solution was useful only in tendrils less 
than 2 mm. in length. A mixture of one part distilled water 
and one part saturated solution of bichromate of potassium 
retained the structures fairly well in many cases, as did also 
Weaker solutions of the same. : 
- y far the best results were obtained by the use of acetic 
a of the following composition: 1 part glacial acetic acid; 
Parts absolute (or 96 per cent. ) alcohol; 3 parts chloroform.? 
Ry na horizontal position. The action of the fluid will 
Se it at first to curve slightly, and then to regain its former 
Poettion. After two or three oscillations of this sort it will 
keep nearly its original form. After remaining 1n 
this fluj : ; : 
S fluid for a time varying from 20 to 30 minutes, it was Te- 
7 P pesnes 
1890, * Am. Soc. of Microscopists, 1890. THomas: Botanical Gazette, Nov. 
® Tan 
; Uary and June, 1888; July, 1890. 
Lex: Microtomists per wet ld ‘10: 
