COLLECTING AND PRESERVING MARINE ALG.T:. 31 



mica. Whether in cask or jar, a layer of salt should be put in, 

 theu a layer of algge, a layer of salt, and a layer of algae, and so on. 

 Specimens are preserved almost in their original condition, for a 

 very considerable time. This method is especially recommended 

 in cases of expeditions when it is impossible to dry specimens on 

 account of the moisture of the climate, lack of room, or lack of 

 time. In the matter* of salt, a fairly fine rock salt is to be used for 

 the larger specimens in the cask and a finer table salt for the more 

 delicate specimens in the jars. Both cask and jars are to be 

 tightly closed, of course, to prevent the leakage of the resulting 

 brine. 



Aqueous Preservatives, — Specimens may be preserved for 

 study in eea-water to which a certain amount of camphor gum or 

 formalin has been added. It is not the intention of this article to 

 enter upon any especial discussion of the merits of this part of the 

 subject, but simply to mention that as temporary preservatives both 

 of these substances are often of the greatest use. It often happens 

 that one collects a far greater number of specimens than he can 

 care for immediately, or some interruption occurs and it is necessary 

 to postpone mounting some or all of the specimens until a time 

 mc^re or less remote. If camphor gum is strewn in the dish or 

 formalin added, and the specimens kept in the dark, they will 

 remain in good condition for a number of days and suffer little 

 change even in color. It is well to have the specimens lying in a 

 proportionally large amount of water, or the camphor or formalin 

 may fail in its effect. For laboratory purposes, specimens may 

 remain in .formalin solution indefinitely, and if kept in the dark 

 will retain their colors for a very considerable time with but little 

 change. Reds, browns, and blue-greens retain their colors for two 

 years at least, but when exposed to the light, fade quickly. Some 

 reds, such as Forphyras, gelatinize in an aqueous medium, as they 

 do also when being soaked out after rough drying. A little cor- 

 rosive sublimate in the water will prevent this and unless the speci- 

 mens are left in too long, it does not afiect the color. 



Mounting and Pressing. — After the specimens have been col- 

 lected or preserved in various ways, if they are to be incorporated 

 into the herbarium, they must be pressed. In the case of coarse 

 species, they are to be rough dried first, then soaked out. After 



