THE VICTORIAN NATURALIST. 131 



ventilation is unnecessary, but perfect flatness essential. The use 

 ot" cotton wool, with proper ventilation, in most cases, is quite 

 sufficient for a very large number of flowers, especially yellow 

 ones, such as Potentillas, Primroses, Buttercups, and several white 

 flowers, such as Wood Anemones, and Water Ranunculus, which 

 will keep their colour perfectly if dried rapidly and with frequent 

 changes of paper. 



" Here it may be well to mention the advantage of taking 

 off on paper water plants like the Water Ranunculus and the 

 Utricularias. The living specimens should be floated in water, 

 a sheet of white or tinted paper being then placed underneath, 

 and the whole plant carefully lifted so that the water gradually 

 flows off, leaving the specimens with the leaves spread out on the 

 paper. This is troublesome to execute, and requires some 

 practice, but it is essential for success, as it is the only way of 

 getting the dried specimens to resemble the living plant. With 

 such plants cotton-wool is only necessary for the flowers. Several 

 blue flowers, such as the Forget-me-nots and smaller Gentians, 

 do very well with absorbent cotton-wool, but the colour of 

 Campanulas usually goes, unless dried with considerable heat 

 from the sun or by crossing with a warm flat iron ; yet even so 

 it is often not permanent. 



" Many flowers, especially those of reddish or purple tints, and 

 several that are white, will not keep their colours if merely dried 

 with cotton wool. Here the use of acids is imperative. Of these 

 the best is sulphurous acid. Its use was first introduced into this 

 country some years ago by Mr. Claridge Druce, F.L.S., an 

 Oxford chemist, well known as the editor of the Oxfordshire 

 Flora, and one of our leading field botanists. He received it 

 from Dr. Schonland, and it had been previously used in the 

 herbarium of the Berlin Botanical Museum. The proportions 

 of the mixture, as prepared by Mr. Druce, are two parts of 

 sulphurous acid, freshly prepared and of ten per cent, strength, 

 with one part of methylated alcohol of about sixty per cent, 

 strength. The methylation should be preferably with wood 

 spirit, and not with mineral oil. The acid tends, in course of 

 time, to become oxidised, and is then useless, so that it is best 

 to get a small quantity every year. 



" The use of the acid is simple enough. The flower should be 

 dipped in the mixture for a few seconds, when the colour will 

 rapidly disappear, leaving the flower white. It should then be 

 carefully dried with blotting-paper, care being taken to remove 

 all the acid without bruising the petals. It may then be pressed 

 in the usual way. Cotton-wool should be used for the leaves, 

 which are, as a rule, unaffected by the acid, and should not 

 be dipped into it. When the acid is used, it is best to 

 place cotton-wool only underneath the flowers, and above 



