TAPEWORM PROGLOTTIDS 



237 



TEETH 



Tapeworm Proglottids. Orient pieces 4-5 

 cm. long containing gravid proglottids 

 between glass slides held together by 

 elastic bands. Fix in Bouin's fluid (sat. 

 aq. picric acid, 7 parts; glacial acetic 

 acid, 20 parts; and formalin, 10 parts 

 10-12 hrs. Wash in running water 2-3 

 min. Flood with 10% aq. NaOH (out- 

 lines of uterus become visible deep 

 orange). Rinse in tap water. Flood 

 with 5% HCl 1-2 min. Tap water 10- 

 15 min. Dehydrate in alcohol, clear in 

 xylol and mount in balsam (Dammin, 

 G. J., J. Lab. & Clin. Med., 1937-38, 

 23, 192-194). An oxidation reduction 

 method for stain differentiation is pro- 

 vided by Tapmisian, T. N., Stain 

 Techn., 1945, 20, 11-12. See Parasites. 



Tarsal Glands. Whole mounts can be made 

 by the method described for Sebaceous 

 Glands. They are also known as 

 Meibomian glands. 



Taste Buds. To demonstrate, choose cir- 

 cumvallate papillae, fix in Bouin's 

 Fluid and stain with Hematoxylin and 

 Eosin. See Arey, L. B. et al., Anat. 

 Rec, 1935-36, 64, 9-25. 



Tartrazine (CI, 640), a pyrazolone acid dye 

 of light fastness 4. This bright yellow 

 dye is useful in coloring foodstuffs, light 

 filters, etc. (Emig, p. 46). 



Teeth. The most comprehensive statement 

 of microscopical technique is contained 

 in A. W. Wellings' "Practical Micros- 

 copy of the Teeth and Associated 

 Parts." London: John Bale Sons & 

 Curnow Ltd., 1938, 281 pp. A chapter 

 by Churchill and Appleton in McClung's 

 Technique is also useful. Teeth can 

 be studied from so many different angles 

 that to outline the techniques in a few 

 words is extraordinarily difficult. Their 

 composition of (1) enamel, the hardest 

 tissue in the whole body, with (2) dentin 

 which is highly mineralized and contains 

 the processes of cells but not their nu- 

 cleated bodies plus (3) richly cellular 

 pulp confers numerous obstacles. The 

 wise histologist or pathologist will save 

 valuable time by at once seeking advice 

 from experts in some dental research 

 laboratory. They possess experience 

 and instruments for grinding ana sawing 

 both of which he lacks. Teeth of adults 

 can be prepared for examination in 2 

 principal ways : 



1. Without decalcification. Church- 

 ill and Appleton (McClung, p. 253) 

 recommend, in place of the usual grind- 

 ing method, a cutting technique used by 

 Johnston at Yale. After extraction fix 

 the tooth immediately in formalin. Then 

 dry and fix to wooden block by modelling 

 compound. Sections are then made by 

 the cutting wheels of a power lathe. If 

 necessary they are polished on a Belgian 



stone, dehydrated in alcohol, cleared in 

 xylol and mounted in balsam. 



When one wishes to include the soft 

 as well as the hard parts Chase's tech- 

 nique of petrifaction is advised by 

 them. Fix as desired (say 10% forma- 

 lin) and wash as required. Transfer to 

 aq. gum arable or dextrin of syrupy 

 consistency. Freeze on freezing micro- 

 tome and cut slices with very fine saw 

 (jeweler's). Remove gum arable by 

 washing in water and stain with carmine 

 or hematoxylin. Dehydrate through 

 alcohols to 95%, J to several hours each 

 depending on size of slice. Acetone ^ 

 hr. or more. Cover with thin celloidin 

 in a container to depth twice or more 

 thickness of slice. Leave container 

 top open very slightly permitting evap- 

 oration until celloidin will scarcely flow 

 when container is steeply tilted. Trans- 

 fer with considerable celloidin to con- 

 tainer of heavy lead foil and further 

 evapxjrate until completely hardened. 

 Grind and polish both sides of slice in 

 presence of water. Remove celloidin 

 with acetone and acetone with xylol. 

 Mount in balsam. Sections obtained 

 by this and the Johnston technique can 

 be examined by direct illumination, 

 in the dark field, in ultraviolet light 

 (Walkhoff, O., Dental Cosmos, 1923, 

 65, 160-176), in polarized light (Andre- 

 sen , V . The Physiologi cal and Artificial 

 Mineralization of Enamel. Oslo. Dancke, 

 1926) and by x-ray for which many 

 references are given (McClung, 381- 

 385). 



2. With decalcification. In the par- 

 affin technique, advised by Churchill 

 and Appleton, clip ends of roots of a 

 freshly extracted tooth or drill hole. 

 Fix in 4% formalin. Dry with towel 

 and seal openings to pulp with celloidin. 

 Quickly dry. Decalcify in 10% hydro- 

 chloric acid C.P. 10 days or more testing 

 with needle. Running water, 24 hrs. 

 95% ale, 24 hrs. Abs. ale, 5 hrs. Chlor- 

 oform, 1 hr. Equal parts chloroform 

 and 45°C. paraffin in glass stoppered 

 bottle on top of oven (oven 58°C.) over 

 night. ^ hr. each in following paraffins 

 (1) 42-46°C., (2) 52-56°C. ancl (3) 58- 

 60°C. within oven. Imbed in a mix- 

 ture of 235 cc. 52-56 °C. paraflan and 15 

 cc. beeswax. See Paraffin Sections. 



In the celloidin technique (Churchill 

 and Appleton) cut off apex of tooth or 

 drill a hole to pulp through crown. 

 Fix in 4% formalin, buffered to counter- 

 act acid, 45 hrs. for single teeth. (Wash 

 in water) change to 80% ale. 95% ale. 

 2 weeks + depending on size. Abs. 

 ale. 2 weeks -f, abs. ale. (exposed to 

 anhydrous copper sulphate, see Alco- 

 hol) 2 weeks -f . Equal parts abs. and 



