.194 DR. HORATIO WOOD ON Fl;E8II WATER ALG.E. 



The Vaiichcrias, which grow frequently on wet ground, as well 

 as submerged, fruit in the early spring and summer in this lati- 

 tude, and are therefore to be collected at such times, since they 

 are only worth preserving when in fruit. 



In regard to Alga3 which grow on trees, I have found but a 

 single species, and do not think they are at all abundant in this 

 latitude. Further south, they seem to be the most abundant 

 forms. 



As to the preservation of Alg£e, most of the submerged species 

 are spoiled by drying. Studies of them should always, when 

 practicable, be made whilst fresh. Circumstances, however, will 

 often prevent this, and I have found that they may be preserved 

 for a certain period, say three or four months, without very much 

 change, in a strong solutimi of acetate of alumina. 



An even better preservative, however, and one much more easily 

 obtained, is carbolic acid, for 1 have studied Desmids with great 

 satisfaction which had been preserved for live or six years in a 

 watery solu^on of this substance. In regard to the strength of 

 the solution, I have no fixed rule, always simply shaking up a 

 few drops of the acid with the water, until the latter is very de- 

 cidedly impregnated with it, as indicated by the senses of smell 

 and taste. 



Almost all species of Alg£e which are firm and semi-cartilaginous, 

 or almost woody in consistency, are best preserved by simply dry- 

 ing them, and keeping them in the ordinary manner for small 

 plants. The fresh-water Algse which bear this treatment well 

 belong to the Phycochromophycece^ such as the Nostocs, Scytonejua, 

 &c., the true confervas not enduring such treatment at all. When 

 dried plants are to be studied, fragments of them should be soaked 

 for a few minutes in warm, or for a longer time in cold water. 



The only satisfactory way that Algte can be finally prepared for 

 the cabinet is by mounting them whole or in portions, according to 

 size, for the microscope. Of the best methods of doing this the 

 present is hardly the time to speak ; but a word as to the way of 

 cleaning them will not be out of place. Many of them, especially 

 the large filamentous ones, may be washed by holding them fast 

 upon an ordinary microscope slide, with a bent needle, or a pair of 

 forceps, and allowing water to flow or slop over them freely, whilst 

 they are rubbed with a stiffish camel's-hair pencil or brush. In 

 other cases, the best plan is to put a mass of the specimens in a 



