12 PKOCEEUINGS OF THE 



Miss M. Ratiibone exhibited a series of specimens preserved by 

 submitting tht^iii to the action of formalin vapour, as sliown in the 

 following statement : — 



Some years ago it occurred to me to try to find some method 

 of preserving [)lants uhicli would not destroy either their form or 

 colour. I began by trying liquid paraftin, and this at first gave 

 very promising results ; but after a time the specimens became 

 mouldy, and, if antiseptics such as salicylic acid were added, the 

 colour disappeared. 



It then occurred to me to try formalin vapour, hoping that in 

 this way the tissues of the plants might be hardened, and at the 

 same time that the colour might be preserved. Unfortunately, 

 as these specimens show, the results have fallen far short of ray 

 ideal ! The colour fades after a time, and the stalks and petals 

 often become limp. However, in plants preserved in this way, 

 the microscopic characters of the tissues and the form of the 

 flower and relationship of its parts are less altered than in dried 

 specimens, whilst for travellers specimens preserved in this way 

 are lighter and more convenient to carry than plants preserved in 

 spirit. 



I found that it was best to dilute the formalin witii water (one 

 part formalin to one or two parts of water), and possibly an eveu 

 weaker solution might answer. Cotton-wool soaked in this solu- 

 tion is put at the bottom of the bottle, or it may be tied round 

 the stalks of the plants, enough being used to ensure a damp 

 atmosphere. Of course the bottles or boxes in which the plants 

 are kept ought to be air-tight, and I found that candle-grease 

 dropped over the cork answered very well. 



These plants were bottled in 1917, as last summer I was 

 moving about and not aide to make any further experiments. 

 I have also brought a bottle of African Marigold in salicylic acid 

 and liquid paraffin, bottled in 1912. It M'as quite the best of my 

 paratHn specimens, most of which are deplorable objects, and I do 

 not think there is much to be said for this method, as it has all 

 the drawbacks of alcohol and none of its advantages. 



As regards formalin, I might add that I have found that a 

 1/10 solution in water is quite good for freshwater Algie. I have 

 some bottled in 1911, in which the chlorophyll body in Spirof/)/ra, 

 which shrivels up so easily with most reagents, still shows quite 

 distinctly. 



The experiments were carried on rather under difficulties, as 

 I was busy witli war-uork in a rather out-of-the-way place and 

 it was not verv eas}^ to get suitable bottles and other materials, 

 to say nothing of flowers, which were not very plentiful in that 

 locality ; but I thought that some of the other Fellows of the 

 Society might like to try this method in spite of its drawbacks, 

 and I also hoped that somebody niiglit be able to suggest improve- 

 ments in the technique. 



The following engaged in the subsequent discussion : — Mr. E. G. 

 Baker, Mr. F. N. Williams, Mr. J. C. Shenstone, Mr. (x. C. 



