THYMONUCLEOHISTONE 



339 



TICKS 



2 min. Leucobasic fuchsin, lJ-2 hrs. 

 Sulphurous acid bath, for sufficient 

 time to remove the free untreated 

 leucobasic fuchsin (2-3 changes). Tap 

 water, 10-15 min. Counterstain, if 

 necessary, with aq. or ale. fast green. 

 Dehydrate, clear and mount in the 

 usual manner, or follow Triethyl Phos- 

 phate technique. 



See Aldehydes for discussion of spe- 

 cificity of Feulgen reaction and Lessler, 

 M. A., Arch. Biochem. and Bioph., 

 1951, 32, 42-54 who thinks that it 

 should be feasible to correlate deter- 

 minations of color intensity of gelatin 

 DNA preparations of known DNA con- 

 centration with that of Feulgen stained 

 nuclei and thus measure approximately 

 the nuclear DNA content. Lessler 

 specifies certain sources of e.xperimental 

 error to be guarded against. 



The histophotometric measurement 

 of DNA in the course of embryonic 

 development is described by Lison, 

 L. and Pasteels, J., Arch, de Biol., 

 1951, 62, 1-43. A biometric investiga- 

 tion of their technique is provided by 

 Martin, L., Arch, de Biol., 1951, 62, 

 45-64. 

 Thymonucleohistone. Technique for di- 

 electric properties, Lars-Goran, All- 

 g^n. Acta Phj^siol. Scand., Suppl. 76, 

 22, 140 pp. 

 Thymus. Isolation en 7nasse of nuclei from 

 Behrens' method as modified by Mayer, 

 D. T. and Gulick, A., J. Biol. Chem., 

 1942, 146, 433-440. 

 Thyroid. For routine purposes Zenker fixa- 

 tion and hematoxylin and eosin staining 

 of paraffin sections is suggested. If one 

 is interested in the colloid, its appear- 

 ance after various fixations, its shrinkage 

 patterns and the significance of its 

 acidophilic and basophilic staining are 

 described by Bucher, D., Zeit. f. Zellf. 

 u. Mikr. Anat., 1938, 28, 359-381. The 

 effect on colloid of different agents for 

 dehydration and clearing is described 

 by Ralph, P., Stain Techn., 1938, 13, 9- 

 15. A method for determination of the 

 volume of colloid is given by Stein, H. 

 B., Am. J. Anat., 1940, 66, 197-211. 



The shape of thyroid follicles can be 

 distinguished but imperfectly in sec- 

 tions unless reconstructions are made 

 from serial sections. For an excellent 

 method of viewing entire, isolated 

 follicles see Maceration. The localiza- 

 tion of unsuspected masses of follicles, 

 not present in the gland, in the neck 

 tissues of experimental animals can be 

 accomplished, by supravital staining 

 with Naphthol Blue. 



Many methods are available for the 

 detailed examination of the secretory 

 epithelial cells not requiring their 



special adjustment to the thyroid gland. 

 See Mitochondria, Microchemical 



methods, etc. The Brazilin-Wasser- 

 blau technique is recommended for in- 

 cellular secretion antecedents. If the 

 Golgi apparatus is to be investigated 

 consult Welch, C. S. and Broders, A., 

 Arch. Path., 1940, 29, 759-772. A fine 

 beginning has been made in the direct 

 study of vacuoles within the follicles in 

 living mice by transillumination after 

 the fashion of Knisely (Williams, R. G., 

 Anat. Rec, 1941, 79, 263-270). Minute 

 instructions for demonstration of blood 

 vessels and lymphatics and results 

 which are to be expected are given by 

 Rienhoff, W. F., Arch. Surg., 1931, 23, 

 783-804. For fluorescence see Grafflin, 

 A. L., J. Morph. and Physiol., 1940, 67, 

 455-470. Effect of Thiourea on thyroid 

 secretion (Thomas, O. L., Anat. Rec, 

 1944,89,461-469). 

 Ticks. The following method for softening 

 and sectioning is an adaptation by Miss 

 Slifer of the Slifer-King technique for 

 grasshopper eggs (Slifer, E. H., and 

 King, R. L., Science 1933, 78, 366-367). 

 Drop animal into dish of Carnoy-Le- 

 brun. After 5 min. place under binocu- 

 lar and puncture with a glass needle. 

 Allow fixative to act for at least 20 min. 

 longer. (Variations in the size of the 

 puncture and in the length of time for 

 fixation should be tried.) Transfer to 

 70% alcohol colored a light yellow with 

 iodine over night. If alcohol is colorless 

 next morning let stand a few hours 

 longer. Repeat if necessary. At this 

 point (or somewhat earlier) it is well to 

 make a larger incision in the animal 

 with a scalpel. The viscera should now 

 be well-hardened and should not ooze out 

 through the hole. 70% alcohol, several 

 hrs. 70% alcohol containing 4% phenol, 

 2 or 3 days. 95% alcohol 2 hrs. Anilin 

 oil, several hrs. Chloroform (2 changes 

 of 5 min. each). Paraffin about an hour. 

 Imbed and block. Trim block away so 

 that viscera are just exposed, at the 

 point where sectioning is to begin. 

 Place block in water containing 4% 

 phenol. Be sure that the cut surface is 

 under water and examine occasionally to 

 see that air bubbles do not form on it. 

 After 3 days a swelling of the tissues 

 should be noticeable so that they pro- 

 trude a little beyond the cut surface of 

 the paraffin. If this has not occurred, 

 cut away a little more and soak several 

 days longer. Trim block, place on 

 microtome and section 5-7 microns. 

 Work rapidly once you have begun. A 

 slight delay between sections will allow 

 the cut surface to dry. If, for any 

 reason, it is necessary to stop wet a 

 scrap of paper and stick it to the cut 



