1892.] THE MICEOSCOPE. 149 



about six or seven inches, split vertically to the flat sides, and a 

 notch cut from the inside of each jaw forming the sides of the 

 split, so that they may securely grasp the neck of the one-ounce 

 vial. Having secured a sufficient number of samples from local- 

 ities whose names and descriptions are recorded in the book, they 

 are taken home and carefully examined under the microscope. 

 Always enter the names of localities in a permanent record, and 

 label each vial with the name of locality and date of gathering. 

 It will save many regrets. If any region gives sufiicient prom- 

 ise it should be visited again and a larger quantity of material 

 secured. This time the outfit consists of a lard pail containing 

 three or four fruit cans fitting one into another, and a self-sealing 

 fruit jar. The top sediment is carefully gathered and put into 

 the cans to settle, which, when enough has been obtained, is put 

 into the jar, sealed up, and carried home. A portion is taken out 

 for examination as it is. The rest is strained through lace — mos- 

 quito-netting will do. This takes out the filamentous forms that 

 interfere with the next operation. Desmids usually occur as free 

 or single cells ; but some beautiful forms are usually joined into 

 filaments, and these will be found in the unstrained sediment. 

 After straining the material is put into one-ounce vials, a little in 

 each. The vials are filled with fresh water and set aside in good 

 light until the next day, or sometimes until the second day, when 

 the desmids will be found on the surface of the sediment, or. if 

 entirely successful, they will be found separated from it by a layer, 

 the mucus before spoken of. They may be removed without dis- 

 turbing the sediment by carefully using a rubber-capped pipette. 

 This material will be made up of nearly clean desmids, and is 

 much more satisfactory for examination than the usual mixture 

 of desmids and dirt. If the operation is not entirely successful 

 and some sediment is found, it may be sometimes repeated, but 

 it is best to be careful (and hence successful) the first time. To 

 preserve this cleaned material, which would otherwise soon be- 

 come foul, it may be put into a one-ounce vial of w^ater with five 

 drops each of ghcerine and strongest carbolic acid. The acid 

 will preserve it and the glycerine will pi-event loss by drying out 

 under the microscope, which is very provoking when one is study- 

 ing a rare form and forgets to renew the v^^ater. This preserva- 

 tive answers as a mounting fluid unless it is desired to preserve 

 the color, in which case carbolic acid must not be used. Pure 

 glycerine has preserved a fine green color for several years, but 

 the endochrome has always been shrunk from the cytioderm. 

 The slides must' be kept from the light as much as possible to 

 prevent bleaching. Having generally wished to get rid of the 

 cell contents not much can be said as to their preservation. Time 

 and natural causes are principally relied upon for their removal, 

 as no chemicals have been tried that do not act injuriously upon 



