ZOOLOGi' AND BOTANY, MIOKOSOOPY, ETC. 1043 



cent, spirit, to whicli 1- 5-2-0 per cent, tincture of iodine has been 

 added. The iodine is afterwards removed by immersion in absolute 

 alcohol, until the teeth become white. 



For staining, alcohol or aqueous solutions of borax-carmine gave the 

 best results. From the absolute alcohol the teeth are removed to 

 nmning water from 15 to 30 minutes, and then placed in the stain. 

 In the watery solution of borax-carmine they remain one or two, in the 

 spirituous two or three, days. They are then transferred to acidulated 

 70 per cent, spirit (70 per cent, spirit 100 ccm., acid, muriat. 1 • 0)_in which 

 they remain, the watery ones stained at least 12, the alcohol-stained ones 

 24 to 36 hours. This done, they are immersed for about 15 minutes in 

 90 per cent, spirit, and then for half an hour in absolute alcohol, after 

 which they are transferred to some ethereal oil for twelve or more hours. 



The ethereal oil is then quickly washed off the objects' with pure 

 xylol, and then they are placed for at least 24 hours in pure chloroform. 

 After this they are passed into a solution of balsam in chloroform. The 

 balsam is prepared by drying, in a water-bath heated gradually up to 

 90°, for eight hours or more, until when cold the mass will crack like 

 glass on being punctured. Of this balsam so much is added to the 

 chloroform as to make a thin solution, in which, as before mentioned, the 

 teeth lie for 24 hours. After this time as much balsam is added to the 

 solution as will dissolve. When no more balsam will dissolve, the teeth 

 and a sufficiency of the balsam are poured into a vessel and heated up to 

 90° in a water-bath until the mass when cold shall be hard as glass. 

 When the balsam is sufficiently set the teeth are carefully picked 

 out, placed in a vice, and thin discs are cut from them with a fret-saw, 

 water being allowed to trickle over them the while, and then they are 

 ground in the usual way. The preparations are mounted in chloroform- 

 balsam. 



Preparing large Sections of Lung.* — Dr. G. S. Woodhead makes 

 large sections of lung for demonstrating morbid appearances as 

 follows : — Make the first incision through the lung in the direction in 

 which you wish to have your sections. The second incision is made 

 parallel to the first and not more than half an inch from the first. 

 The section should then be placed in a flat dish on a layer of lint, and 

 covered with several layers of lint, and over this a piece of plate-glass 

 to keep the section flat and submerged. After being five or six weeks 

 in the Miiller, the sections are washed for about 24 hours in water. 

 The slice is then placed in a mixture of 5 parts mucilage (B.P.) and 4 

 parts of syrup made by boiling 20 oz. of sugar in a pint of water. In 

 winter 3 parts of syrup will suffice. Two drops of carbolic acid to the 

 ounce prevent formation of fungi. After soaking in this for 48 hours 

 or more, the slice is taken out for sectioning, dried with a soft cloth, 

 then placed in B.P. mucilage for a few minutes, and then transferred to 

 the freezing plate of the microtome. The microtome used is a modifica- 

 tion by Dr. A. Bruce of the best features of the Hamilton and Williams 

 microtomes. From time to time the slice must be banked up with 

 gum, and when nearly frozen pare down the tissue to the level of the 

 rails with a long thin knife. In front of the microtome place a flat 

 white dish filled with warm distilled water, and in which is also placed 

 a flat glass, larger than the slice, and which will eventually serve as 



* The Microscope, viii. (1888) pp. 272-5. 



