190 Mr J. M. Macfarlunc on the 



EXPLANATION OF PLATES. 

 Plate VII. — Portion of branch of Lepidophloios laricinum bifur- 

 cating. Below the point of dichotomy are two cicatrices or tuber- 

 cles pretty far apart, while above there are several developed in 

 regular order. The lower part of the branch is destitute of tubercles, 

 and exactly resembles an ordinary Lepidophloios ; the upper portion 

 with tubercles is what has hitherto been designated Halonia. 



Plate VIII. — Pig. 1. Supposed cone of Lepidophloios laricinum 

 with cone-stalk. The latter, in all probability, articulated with a 

 tubercle of the Halonia branch. 



Fig. 2. Isolated cone scale. 



Fig. 3. Portion of stem of L. larimnmi 3 inches in diameter, 

 natural size. 



Fig. 4. Portion of cone-stalk, |- inch in diameter, magnified. 



Fig. 5, a, h, c. Stages in the development of the cone. 



Notes on the Action of some Aniline Dyes on Vegetable 

 Tissues. By John M. Macfarlane, B.Sc. 



(Read 14tli July 1881.) 



The action of the aniline dyes on vegetable and animal 

 tissues has recently been carefully studied, and the results 

 obtained have proved satisfactory. I now propose record- 

 ing some of the more important methods arrived at. 



I. Staining of Laticiferous Vessels. — Every botanist must 

 have experienced the difficulty of obtaining thoroughly good 

 preparations of laticiferous vessels. Sachs* recommends 

 boiling in dilute potash ; but, while tolerably good sections 

 may be obtained in this way, several difficulties are en- 

 countered. The points to be aimed at in preparing this 

 tissue are (a) the coagulation. of the latex, so that it may 

 continue to fill the vessels ; (6) the staining of the cut sec- 

 tions, so that the vessels may be distinctly differentiated from 

 the surrounding cellular substance ; (c) the successful mount- 

 ing of these, so that the tint may be permanently retained. 

 The first part of the process is best accomplished by ob- 

 taining, for example, a large and entire root of Scorzo7iera, 

 so that extensive bleeding may be prevented. A suitable 

 * Text-book of Botany, p. 110. 



