250 The Microscope. 



of tubes will be foun 1 penetrating each silk. If the silk thus 

 specially fertilized be mounted in some suitable medium (water 

 will answer), and examined, many of the grains may be seen in 

 the act of discharging their contents. I have never been able to 

 ascertain exactly how far the tube penetrates the stigma, but not 

 more, I think, than a millimetre or two. The protoplasm after 

 leaving the pollen tube, by pressure from behind and capillary 

 attraction, passes rapidly to the ovary. It passes out in a con- 

 stant stream and takes about fifteen minutes to empty the grain. 

 — J. M. Barrow^. 



Mounting fresh water Alg.e. — I have tried many media for 

 mounting fresh water Algse, and find the best to be a solution of 

 acetate of potash in water. It does not alter the chlorophyll, 

 and preserves the color fairly well in most species — perfectl}' in 

 some. One fluid ounce of water to half an ounce of potash is 

 the recipe. Should anything like crystals form in the mount, 

 the solution should be weakened by the addition of water. Far- 

 rant's medium is the next best ; I often use it, and produce most 

 satisfactor}' results ; but the object to be mounted in it must 

 previously remain for a couple of minutes in the " 1, 2, 3," or 

 " Gwa " mixture. The " Gwa " mixture is composed of glycer- 

 ine 1 part, water 2 parts, alcohol 3 parts. After this preparation 

 the Farrant does not effect much alteration of the chlorophyll. — 

 H. W. Lett'. 



Ringing mounts. — For peventing the finishing cement from- 

 running under, I have been using a solution of gelatin and gum 

 arable, about 60 grains of each to the fluid ounce of water and" 

 colored with some aniline dye. In using it, ring a narrow band 

 of it around the edge of the cover glass and slide and allow to- 

 dry ; when dry it is ready for the finish. It is best to apply two or 

 more coats of the gelatin and gum solution so as to ensure com - 

 plete covering for the resinous medium. Having tried it for 

 some time, it seems to be satisfactory and does very well- 

 Since parafin has been recommended for the same I have tried 

 it, and it is as good, but requires quicker manipulation. Parafin 

 is the best substance for pure carbolic acid ceinentings, as all 

 other cements are disolved or softened by phenol. — /. E. Huber, 

 Ph. G\ 



2 An. Rep. Am. Postal Micros. Soc. 3 Science Gossip. 4 Meyer Brothers Druggists 



