KULTSCHITZKY'S HEMATOXYLIN 173 



LEAD 



Kultschitzky's Hematoxylin is 1 gm. hema- 

 toxylin dissolved in a little alcohol made 

 up to 100 cc. with 2% aq. acetic acid 

 (Lee, p. 526). 



Lac, a crimson dye obtained from resinous 

 incrustation caused by the insect, Coc- 

 cus lacca, of Siam, Indo-China and 

 Southern India. This dye, introduced 

 into England about 1790 A.D., became 

 an important article of commerce in 

 competition with cochineal of Mexican 

 origin, but before long proved inferior 

 to cochineal and was no longer im- 

 ported. The crimson dyes, Kermes, 

 cochineal and lac have played im- 

 portant parts in the history of civiliza- 

 tion (Leggett, W. F., Ancient and 

 Medieval Dyes. Brooklyn: Chemical 

 Publishing Co., Inc., 1944, 95 pp.) 



Lacmoid, an indicator similar to Resorcin 

 Blue. 



Lacteals, see Lymphatic Vessels. 



Lactoflavin, see Vitamin Bj. 



Lactophenol, a fixative for Bilharzial Cer- 

 cariae. See Lactophenol-cotton blue 

 technique under Fungi. 



Laidlaw's Methods. 1. For inclusion bodies 

 (quoted from Pappenheimer, A. W. and 

 Hawthorne, J. J., Am. J. Path., 1936, 

 12, 625-633, see colored figure, who used 

 it for cytoplasmic inclusions in liver 

 cells). Fix in sat. aq. corrosive sub- 

 limate 100 cc. -f 5% glacial acetic acid 

 or in Zenker's fluid without acetic. 

 Imbed in paraffin, cut sections 3m. Re- 

 move paraffin and pass down to water. 

 Weigert's iron hematoxylin (2%) 5min. 

 Differentiate in 0.5% acid alcohol. 

 Rinse in tap water, then aq. dest. 1% 

 aq. acid fuchsin 5-15 min. Rinse in 

 aq. dest. Mordant in 1% phospho- 

 molybdic acid 30 sec. Rinse in aq. dest. 

 Differentiate in 0.25% orange G in 70% 

 ale. Dehydrate, clear ana mount in 

 balsam. 



2. For silver staining of skin and tu- 

 mors (Laidlaw, G. F., Am. J. Path., 1929, 

 5, 239-247). Fix in Bouin's fluid or in 

 10% neutral formalin for 3 days. (To 

 make the Bouin's fluid he uses, add 100 

 cc. commercial formalin and 20 cc. glacial 

 acetic acid to 300 cc. tap water and satu- 

 rate with picric acid). Fix paraffin 

 sections to slides by Masson's Gelatin 

 Glue. Wash Bouin sections for 20 min. 

 in running water, and formalin ones for 

 5 min. 1% ale. iodine, 3min., rinse in tap 

 water. 5% aq. hypo (sodium thiosul- 

 phate), 3 min., rinse in tap water. 

 ^% aq. potassium permanganate 3 min., 

 rinse in tap water, 5% oxalic acid, 5 min. 

 Wash in running water, 10 min. Aq. 

 dest. 3 clianges in 5-10 min. to clean 

 before adding silver. Heat stock Lith- 

 ium Silver solution to 50°C. and stain 

 in oven for 5 min. Pour aq. dest. over 



both sides of slides. Flood sections fre- 

 quently for 3 min. with 1% formalin in 

 tap water. Again rinse both sides of 

 slides with aq. dest. 1:500 yellow gold 

 chloride in aq. dest. in Coplin jar at 

 room temperature, 10 min. Rinse both 

 sides with aq. dest. Pour on 5% oxalic 

 acid 10 min. Rinse in aq. dest. Pour 

 on 5% hypo changing as often as it be- 

 comes turbid, 10 min. Wash in running 

 water. Counterstain if desired. De- 

 hydrate, clear and mount in usual way. 

 Reticulum, black threads; collagen red- 

 dish purple. 



Lake Ponceau, see Ponceau 2R. 



Lampblack. A colloidal suspension of lamp- 

 black is an excellent substance to inject 

 intravenously to demonstrate phago- 

 cytosis, especially by monocytes. Mc- 

 Junkin, F. A., Arch. Int. Med., 1918, 

 21, 59-64, advised adding 0.4 gm. of 

 carefully pulverized lampblack to 100 cc. 

 2% gelatin in aq. dest. Inject intra- 

 venously with 5-9 cc. 10% aq. sodium 

 citrate, as in the case of Higgins'Ink. 

 The method has been slightly modified 

 by Simpson, M. J., J. Med. Res. ,1922, 

 43, 77-144; Wislocki, G. B., Am. J. 

 Anat., 1924,32, 423-445; and Lang, F.J., 

 Arch. Path., 1926, 1, 41-63. 



Lanacyl Blue BB (CI, 210), an acid monoazo 

 dye which colors cell walls and paren- 

 chymatous cells light blue but less well 

 than other blue acid dyes (Emig, p. 35). 



Lanacyl Violet B (CI, 207), an acid monoazo 

 dye of light fastness 3. Directions for 

 staining plant tissue and fungous my- 

 celia (Emig, p. 35). 



Langerhans, see Islets of. 



Lard, reactions in tissue to fat stains after 

 various fixations (Black, C. E., J. Lab. 

 & Clin. Med., 1937-38, 23, 1027-1036). 



Large Intestine. The conditions that in- 

 fluence the appearance of sections are 

 easier to guard against than in the Small 

 Intestine because of the absence of villi 

 and greater uniformity of contents. 

 The pronounced influence of degree of 

 distention is described and well illus- 

 trated by Johnson (F. P., Am. J. Anat., 

 1912-13, 14,235-250). 



Lansing, see Collagen, Elastin. 



Latex-Cast Techniques for study of the 

 circulation have been applied to the 

 spleen by Gall, D. and Maegraith, 

 M. G., Ann. Trop. Med. & Parasit., 

 1950, 44, 331-338, who give good illus- 

 trations of results and references to 

 previous work. 



Lauth's Violet, see Thionin. 



Lead, histological demonstration. 



1. Mallory and Parker's method (Mal- 

 lory, F. B. and Parker, F. J., Am. J. 

 Path., 1939, 15, 517-522) : Fix tissues in 

 95 or abs. alcohol (not formalin). Stain 

 celloidin sections at 54°C. in: 5-lOgm. 



