298 Sykes. — Anatomy and Histology of Macrocystis pyrifera and 
protoplasm in the same way as cellulose, as has been suggested by Russow 1 
and Strasburger 2 , and found by Hill 3 in Finns. 
II. Material and Methods used in this Investigation. 
Material. The material of Macrocystis which was at my disposal con- 
sisted of the young apex of a growing plant, and of two collections of older 
portions of the stem. One of the two collections was made in the Falkland 
Islands, and consisted of pieces of stem of about one-third of an inch 
in diameter, while the other came from Talcahuano Harbour, Chili, and 
was obtained from rather younger plants whose stems varied from one- 
eighth to a quarter of an inch in diameter. The young apex was preserved 
in spirit, and the rest of the material was fixed in a solution of Iodine 
in Potassium Iodide, dissolved in sea-water, and preserved in a Thymol 
solution. All the material was obtained by Mr. Hill in December (1902), 
that is, early in the South American summer. 
I had also the opportunity of examining all stages in the development 
of young plants of Laminaria saccharina, preserved in spirit. These 
young plants were used in investigating anatomical development, while 
older material, preserved in September by Mr. Hill, and in February by 
myself, had been treated in a manner which rendered possible more 
minute histological work. Some of the September material was fixed 
in a solution of Iodine in Potassium Iodide, and the rest in Picric 
acid, both being preserved in Thymol ; but neither of these methods was 
found to be very successful. Various methods of fixation at different 
temperatures were tried as experiments on the February material. 4 
Methods. The methods used in swelling and staining were based 
on those already published by Gardiner 5 and employed by Hill 6 in 
Finns. A solution of Iodine in 10 per cent. Potassium Iodide was found 
to be the most useful swelling agent, and gave good results when the 
material was left in the solution from two to three weeks. 
For staining, a modification of the Safranin method 7 was used in 
conjunction with Aniline blue 8 and London blue. The chief difficulty met 
1 Russow, Sitzb. der Dorpater Nat. Ges., 1882 ; Ann. des Sc. Nat., 6 e ser., t. xiv, 1882. 
3 Strasburger, Bot. Pract., 1884. 
8 Hill, 1. c., p. 598. For a summary of the various views on the origin of callus, see pp. 597-600. 
4 Some of the fixing agents used at the suggestion of Mr. Hill were Picric acid, Iodine in Potas- 
sium Iodide, Piero- Acetic acid, and Picro-Uranium Nitrate, all being dissolved in sea-water, and 
Thymol being used in all cases as a preservative. 
Picro-Uranium Nitrate was found to give the best results, the composition of the solution used 
being as follows : 
50 cc. sea-water. 
•5 gr. Picric acid. 
1 gr. Uranium Nitrate. 
3 Gardiner, Proc. Camb. Phil. Soc., 1898 ; Proc. Roy. Soc., vol. lxii, 1897. 
6 Hill, I. Connecting-threads in Pinus (Pt. 1 of Gardiner and Hill on the Histology of the 
Cell-wall), Phil. Trans. Roy. Soc., Bot., 1901, pp. 83-125. II. Histology of Sieve-tubes in Pinus , 
Annals of Botany, vol. xv, 1901, p. 576. 7 Gardiner, 1. c., 1898, p. 508. 
8 Water blue made up with aniline. 
