138 Chronicles of Science. [Jan., 



minute tubes, also over every part of the sarcoleruma. They frequently 

 anastomose, and the finest branches are not to be seen by the aid 

 of a magnifying power of 200 or 300 diameters. The delicate cha- 

 racter of this investigation is the reason that their finest branches of 

 nerves and tracheae have never been observed before. The result of 

 Dr. Beale's observations is, that the membranous sarcolemma of insect 

 muscle is composed of very fine air-tubes and nerve-fibres imbedded in 

 a transparent material, so incorporated with it as to form a part of its 

 substance. This elaborate sarcolemma is developed with wonderful 

 rapidity, the entire muscle being in some cases doubled in size in the 

 course of two or three days. 



The use of dyes for the examination of organic structures has been 

 well illustrated by Dr. Beale's papers on the growth of tissues. He 

 found that when tissues were stained with carmine, a permanent stain 

 was acquired by certain portions only of the tissue, including those 

 which are generally supposed not to have reached their ultimate grade 

 of development, and excluding those which have evidently undergone 

 a structural process. Graduated colour was thus given to tissues 

 which probably were in a course of gradual transition into "formed 

 matter." Iodine has long and deservedly been in repute as a test for 

 starch and cellulose, but apart from this, it does not avail much as a 

 dye. The compounds of aniline contain some which stain parts not 

 coloured by carmine. Thus magenta, one of the most brilliant, has 

 distinctive qualities, and selective staining power as great as that of 

 carmine, and still more limited. Altogether unattracted by pure 

 cellulose, it at once seizes those portions of " formed matter" which 

 come under the head of " secondary layers." A dye for the structures 

 left uncoloured by both magenta and carmine, is, however, still a desi- 

 deratum. A satisfactory contrast of colour is not obtained by these 

 two dyes ; mauve, Hoffman's violet, aniline brown, picrate of aniline, 

 and turmeric, all dye as magenta, but the purples alone approximate to 

 the desired contrast. Aniline green produces results capricious and 

 unsatisfactory, and the ordinary aniline blue of commerce proved under 

 the hands of Mr. Walter Abbey, an instructive failure. The tissue 

 came out magnificently coloured, but the colour was mechanically and 

 partially distributed, and was entirely discharged by alcohol. The 

 second blue effected the desired contrast, but at the expense of the 

 carmine, instead of the magenta ; and the blue substitute for car- 

 mine possessed intense and splendid colouring power, even more 

 brilliant by artificial light than by daylight. 



Mr. W. H. Griffiths describes the appearance of the so-called 

 " contractile vesicle," in the Vorticellidae, as somewhat differing from 

 the received account. He attributes the appearance of contraction to 

 the fact of the vesicle having been removed from the line of focus by 

 the movements of the living animal, and objects therefore to the term 

 contractile. With regard also to the processes from the vesicle sup- 

 posed to have been observed by Lachmann, he believes that they were 

 not branches of the vesicle, but only occasional interpositions of the 

 cilia of the disc between the object and the microscope. If these ob- 



