1885.] 



MICROSCOPICAL JOURNAL. 



25 



contains jute, or is made entirely 

 of that fibre, which also enters into 

 the composition of the cheaper grades 

 of ingrain carpets, matting, twine, 

 and rope. 



M. V^tillart has arranged a scheme 

 for the systematic examination of 

 fibres, which gives the distinctive 

 features of the different ones in a very 

 concise form. It is intended to aid 

 the observer in identifying unknown 

 fibres. The arrangement will be 

 translated and published in our next 

 number. 



When a typical specimen of any 

 fibre is examined, it is usual to pi'e- 

 pare several permanent mounts for 

 the microscope, to be used in com- 

 paring different fibres. To be use- 

 ful such mounts must show the fibres 

 precisely iis they appear when exam- 

 ined in water and glycerin. They 

 are therefore mounted in the same 

 mixture. The mounting is ver\ 

 quickly done, and the preparations 

 are permanent. 



The slides are first prepared with 

 thin rings of shellac, of the proper 

 size to receive ^-inch cover-glasses, 

 and set aside for use as required. 



The fibres having been prepared as 

 described above, by boiling in soda, 

 and separated by needles, are then se- 

 lected for mounting. It is desirable 

 to show all parts of a fibre on each 

 slide. Suppose we have a fibre ten 

 inches in length, and desire to mount 

 it for study. The mount must show 

 both ends of the fibre and different 

 parts along the length. Several such 

 fibres are therefore chosen, placed 

 together in the hand, and pieces cut 

 off" from the ends half an inch long. 

 Then at various places along the 

 length other pieces of the same length 

 are cut off' and the rest rejected. 

 Thus a good set of specimens for 

 mounting is obtained, which is sure 

 to give all the needed characters — the 

 appearance of the ends, the diameter 

 in different parts, etc. The pieces 

 are placed in the glycerin and water 

 mixture, while the slide to receive 

 them is made ready. 



One of the prepared slides is now 

 selected, placed on the turn-table and 

 a coat of thin shellac laid over the 

 hardened ring. Almost immediately 

 a few drops of the mounting medium 

 are placed within the cell, the speci- 

 mens to be mounted transferred to 

 it, the cover-glass applied, pressetl 

 down gently on the fresh shellac, to 

 which it becomes quickly attached. 

 As the excess of liquid is forced out 

 it is absorbed by pieces of blotting 

 paper. The slide is now set aside 

 and others mounted in the same way. 

 In the course of ten minutes the gly- 

 cerin can be washed awa\' from the 

 surface, under a tap or, as we prefer, 

 by directing a fine stream of water 

 upon it from a chemist's wash-bottle. 

 It is then partly dried with blotting- 

 paper, and in a few moments will be 

 perfectly dry. A ring of shellac is 

 then run around the cover-glass to 

 ensure against leakage, and the slide 

 set aside until a convenient time for 

 finishing it, which may not be for 

 several weeks. 



The finishing consists in a coat 

 of asphalt and gold size in equal 

 parts, followed by a ring of asphalt 

 alone. 



Revivification of Infusoria. 



BY JABEZ HOGG. 



The mysterious revivification of 

 many of the minuter forms of infuso- 

 rial life, notably rotifers, or as the}' 

 are more commonly- called, wheel 

 animalcules, cannot fail to surprise 

 and interest those who may for the 

 first time witness their evolution from 

 a few small particles of earth or dust. 

 A drop of water is sufficient to awaken 

 fi^om their longest sleep whole colo- 

 nies of desiccated rotifers — will in a 

 few minutes restore them to life and 

 vigor and send them on their way re- 

 joicing, just as their ancestors had 

 gone in ages past. 



I have previously described a series 

 of observations made under the micro- 

 scope which seemed to show the inde- 

 structibility of those delicately and 



