ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 717 



•9 to 1 cub. cm., carbon di sulphide "75 cub. cm. For the 

 injection of entire subjects by the aorta Teichmann uses first 

 of all a thinner mass consisting of chalk, 500 gr., vermilion 

 100 gr., linseed oil 120 cub. cm., carbon disulphide 150 cub. 

 cm. ; he then employs a stiller preparation of chalk 1000 gr., 

 vermilion 200 gr., linseed oil 200 cub. cm., carbon disulphide 

 100 cub. cm. White masses, especially adapted for injection 

 of lymphatics, have the following composition : — Zinc white 20 gr., 

 linseed oil 3 cub. cm., ether 2 cub. cm. By addition of colouring 

 matters this mixture forms other combinations. The following pro- 

 portions are in general suitable for a blue mass : Zinc white 15 gr., 

 ultramarine 1 gr., linseed oil 2 to 2h cub. cm., carbon disulphide 

 1 cub. cm. The injection is made slowly by a syringe, the piston of 

 which is provided with a screw-thread and is pushed gradually 

 forwards by a twisting movement. The linseed oil is first boiled 

 for eight to ten hours, and no lead compounds are added to it. 



Wywodzen's Injecting Material.* — D. Wywodzen has, he says, 

 obtained admirable results by using thymol. The proportions are : — 

 thymol 5 parts, alcohol 45, glycerine 2160, and distilled water 1080. 



Mounting in Pure Balsam, j — Dr. S. Marsh, although he cannot 

 too strongly insist upon the use of benzol -balsam wherever practi- 

 cable, yet points out that it sometimes happens in the mounting of 

 substances of considerable thickness that, after all the benzol has 

 evaporated, an insufficient amount of balsam is left behind to fill up 

 the cavity between slide and cover. In such cases, therefore, it is 

 advisable to use pure balsam, which may be done in the following 

 manner : — The object having been previously thoroughly dehydrated 

 by immersion in absolute alcohol, it is to be thence transferred to a 

 little good turpentine or benzol, where it should remain until perfectly 

 transparent. It is now to be placed iu the centre of a slide which 

 has been gently warmed, and a drop or two of fresh fluid balsam 

 added, the greatest care being taken to prevent the formation of air- 

 bubbles. Should such arise they must be touched with the point of 

 a heated needle, which will cause them to burst and disappear. The 

 chief difficulty of the process has yet to be encountered in the appli- 

 cation of the cover, for it is during this procedure that the develop- 

 ment of air-bubbles is most likely to take place. This annoyance 

 may, however, be entirely avoided by taking the simple precaution 

 of dipping the cover into turpentine before it is applied, when it will 

 be found that "you can't get air-bubbles even if you try." The 

 author adds that it is to the courtesy of Mr. J. A. Kay, late of 

 Chatham, that he is able to give his readers the benefit of this 

 practical " wrinkle." 



Centering Objects on the Slide.J — Dr. Marsh considers that the 

 appearance of a slide is vastly improved if the preparation be placed 



* St. Petersb. Med. Wochenschrift, No. 51. Cf. Jabresber. Vircbow and 

 Hirsch for 1880, p. 2. 



f 'Microscopical Section-cutting,' 2nd ed., 18S2, p. 109. 

 J Ibid., p. 101. 

 Ser. 2.— Vol. II. 3 C 



