IIARDWICKE'S SGIENCE-GOSSIP. 



233 



abound in these and most other plants. The sub- 

 sequent differentiation of the secreting organs of 

 the pitcher into aqueous, saccharine, and acid, 

 would ioWow pari passu with the evolution of the 

 pitcher itself, according to those mysterious laws 

 which result in the correlation of organs and 

 functions througliout the kingdom of Nature ; and 

 which, in my appprehension, transcend in wonder 

 and interest those of evolution and the origin of 

 species. These remarks will, I iiope, lead you to 

 see that thougli the processes of plant nutrition 

 are, in general, extremely different from those of 

 animals, and involve very simple compounds, yet 

 that the protoplasm of plants is not absolutely 

 prohibited from availing itself of food, such as that 

 by which the protoplasm of animals is nourished, 

 under which point of view these phenomena of car- 

 nivorous plants will find their place, as one more 

 link in the continuity of nature. 



MICROSCOPY. 



Exuviae of Insects.— Some very interesting and 

 instructive objects for the microscope, and which, 

 moreover, are easily procured, and also easily 

 mounted, consist of the exuviai or cast skins of 

 many species of insects. These may be found in a 

 variety of places; generally on the under side of 

 leaves of plants, or some such protected spot, to 

 which they are attached by their feet, or rather 

 their old shoes, and from which they can be re- 

 moved with a little cave. I find that a good way to 

 mount these exuvite is dry, in a cell sufficiently 

 deep to allow of their retaining their natural posi- 

 tion. Do not use a black background, but view 

 with transmitted light. They show well with spot 

 lens and binocular arrangement. The above will 

 not apply to the larvae of lepidoptera, as they leave 

 their " old clothes " in a small dried heap, which 

 they often devour.—^. Lovett. ■ 



Moller's New Diatomaceen Typen Platte. 

 —I have inspected some of these " Platl;eD," and 

 found that the objects are mounted in a glass cell, set 

 on a glass slide of the usual dimensions, three inches 

 by one inch (the same as the other Typen Platten) ; 

 and for this reason I believe that Mr. P. Kitton's 

 description of the same (Science-Gossip, August, 

 1874, page 176) is somewhat incorrect when he 

 states: "The objects are mounted between two 

 pieces of thin glass ; these are afterwards set in a 

 brass plate . . ." Mr. Baker has supplied me with 

 a safety brass plate for my Moller's Typen Platte 

 No. 1, which has the same dimensions as those 

 given by Mr. Kitton. Perhaps the neic Typen 

 Platte described by Mr. Kitton was inclosed in a 

 similar safety brass plate, and this was taken as 

 forming part of the "Platte." Mr. Iv.'s descrip- 



tion is quite accurate in every other respect, and I 

 only make the above observations in order to pre- 

 vent disappointment to intending purchasers of 

 these "marvellous specimens" when finding that 

 the objects are set on an ordinary glass plate, instead 

 of a brass one, as some of Mr. Norbert's Bands of 

 Test Lines. 1 may just add that my tiew Typen 

 Platte contains 100 diatoms (showing front and 

 side-views, &c.), and that thirteen species of these 

 are not included among those of my Typen Platte 

 No. 1. I am not aware that Herr Moller supplies 

 the new Typen Platte with 80 and 100 specimens, 

 as mentioned by Mr. Slack {llonthhj Microscopical 

 Journal, No. 62, July 1871, pages 41 and 45). I 

 believe the 100-specimens new Diatomaceen Typen 

 Platte is the only one of this kind produced at present 

 by Moller. While on this subject I would suggest 

 that Mdller's Typen Platten of Echinoidea and 

 Holothurid(e, also mentioned by Mr. Slack as above, 

 are well worth a description, and it is to be hoped 

 that Mr. Kitton, Mr. Slack, or any other eminent 

 microscopist, will undertake the task. Herr .Mol- 

 ler has sent to the market a great variety of prepa- 

 rations well deserving the attention of microscopists, 

 especially some new and beautiful sections of hard 

 substances — bones, teeth, shells, spines of Echi- 

 noidea, minerals, &c., and, though last not least, a 

 new Probe Platte, dry, a truly valuable test slide. 

 The other preparations of his, such as sections of 

 wood, selected and arranged diatomace«, &c., are 

 already well known. — A. de Souza Gidmaraens. 



Fixing Arranged Diatoms.— At page 110 of 

 Science-Gossip for 1873, in answer to an inquiry 

 from C. L. Jackson, page 69 of the same year, I 

 explained the method of fixing arranged diatoms, 

 which has been adopted by Mr. J. K. Jackson in 

 his article at page 203 of the current year. My 

 object in writing now is to caution the readers of 

 Science-Gossip not to delay the fixing process 

 until all the diatoms arc arranged, but to secure 

 each one by the breathing process directly it is 

 placed in position (as I suggested to Mr. C. L. 

 Jackson in the article above mentioned), and thus 

 avoid the annoyance of having an hour's work 

 spoiled by the slamming of a door, or by an acci- 

 dental swerve of the arranging tool. It should also 

 be noted that when a diatom is taken from a drop 

 of water and placed on the gummed surface, being 

 moist, it immediately adheres thereto, and any 

 attempt to move it results in its utter destruction, 

 unless the gum has previously been thoroughly 

 softened by the breathing process. With regard to 

 the implement, a simple hair is not well adapted 

 for withdrawing a diatom from a drop of water. 

 The orthodox weapon is a very fine bristle split at 

 the end in such a manner that when pressed on a 

 slide the cleft portion opens like the nibs of a pen, 

 and may then be allowed to close upon the chosen 



