512 SUMMARY OF CURRENT RESEARCHES RELATING TO 



frequent changes of alcohol, to which tincture of iodine had been added. 

 The material was then imbedded either in paraffin or in celloidin. For 

 staining, Bohmer's hematoxylin and eosin, picrocarmin, or iron-alum- 

 ha3inatoxylin were used. 



Demonstrating- Chromosome Reduction in the Microsporocytes of 

 Lilium tigrinum.* — J. H. Schaffner killed stamens of various ages in 

 weak chrom-acetic acid (chromic acid 0*3 grin., glacial acetic acid 

 # 7 c.cm., water 99 c.cin.). The material was then passed through 

 graded alcohols up to 70 p.c, imbedded in paraffin, cut to 10-18 p thick, 

 and stained on the slide. Delafield's hamiatoxylin was found to be the 

 best stain for the chromatin network, and granules and saff ranin-gentian- 

 violet for the nucleoli. 



Demonstrating the Development of Dentine.f — L. Fleischmann 

 examined the tooth-germ of a lower middle incisor of an eight months' 

 human embryo preserved in alcohol. The specimen was prepared by 

 Schaffer's method, being decalcified for several hours in 5 p.c. nitric 

 acid and then imbedded in celloidin ; a radial longitudinal section 

 exhibits the dentine in all stages of development, the earliest traces 

 being at the bottom, whilst on the top is fully developed dentine. The 

 sections are stained after the method of Zachariades with safranin and 

 subsequent treatment with warm 40 p.c. solution of caustic potash, on 

 the slide, until the ground substance is dissolved. 



Studying the Organogenesis of Ovary and Testicle.:}: — G. Sain- 

 niont used a complete series of embryos and ovaries of the cat. The 

 animals were narcotised and then the uterus and adjacent parts were 

 rapidly removed and placed in artificial serum previously heated to 37°. 

 The embryos were then extracted and placed in the fixative ; the larger 

 were sliced into to allow more ready penetration. In embryos 40 days 

 old or so the sexual eminences were removed and fixed separately. The 

 fixative solutions used were the strong Flemming, 24-48 hours, and 

 acetic-sublimate solution, 1-7 hours ; after the latter the objects were 

 washed in iodine-alcohol 40 p.c. for 4-8 hours and then passed through 

 upgraded alcohols. Objects fixed in Flemming were submitted to pro- 

 longed washing in running water for from 8-36 hours according to size. 

 After dehydration in up-graded alcohols paraffin sections were made. 

 The stains used were iron-hasinatoxylin, Flemming's triple stain, and 

 occasionally gentian-violet used hot. It was found that embryos would 

 require 4 or 5 times as much orange as was necessary for the young 

 or adult animal. Good differentiation was obtained by washing the 

 stained sections with alcohol acidulated with 2 or 3 drops of hydro- 

 chloric acid. 



Studying Cytological Changes in the Nectar Glands of Vicia 

 Faba.§ — C. E. Stockhard cut the glands from the stipules with a border 

 of non-glandular tissue and immersed in various fixatives, the most 



* Bot. Gazette, xli. (1906) p. 184 (2 pis.). 



t Arch. Mikrosk. Anat., lxviii. (1906) p. 297. 



X Arch. Biol., xxii. (1905, published 1906) pp. 71-162 (6 pis.). 



§ Bull. Torrey Bot. Club., xxxiii. (1906) pp. 247-62 (2 pis.). 



