258 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(6) Miscellaneous. 



Microscopic Structure of Uric Acid Calculi.* — 8. G. Shattock 

 divides uric acid calculi into two classes, the cancellous and the compart, 

 according as there are or are not lacunae to be found in the sections. 

 Tn the course of his remarks, the author compares the crystals forming 

 calculi with uric acid sediments in urine, and discusses the nature of 

 the nucleus of uric acid calculi. He finds that the nucleus is almost 

 invariably of the same chemical composition as the rest of the stone, 

 but that its structure varies, consisting of loosely arranged crystals 

 resembling " crystalline rubble " in the cancellous variety, while in the 

 compact one it is a dense mass of crystals arranged in radiating columns, 

 and often starting from a small collection of cuboidal crystals. He 

 points out that the essential condition for the formation of crystals 

 must be supersaturation of the urine with uric acid. The paper is 

 copiously illustrated. 



Coloured Plates of Microscopical Preparations. f— Y. Sobotta 

 describes a two-colour autotype process, by means of which the majority 

 of histological preparations may be faithfully reproduced at a compara- 

 tively small cost. In preparing a plate of a section stained with 

 kasmatoxylin and eosin, the stains may be represented by violet and red. 

 A drawing is made first of all of the hematoxylin stained portion alone. 

 This is executed in black with Chinese ink. By means of the autotype 

 process, prints of this are prepared in black, in violet, and in a pale 

 shadowy ground colour. Upon this last print, a drawing is made of the 

 eosin-staining portion alone. This is also done in black. From this 

 are prepared a plate in black and a plate in red. Then a combined print 

 of the violet and the red plate will give a tint two-colour reproduction 

 of the preparation. 



Microchemical Demonstration of Guanin.} — A. de Giacomo de- 

 scribes a method, by which the presence of guanin may be demonstrated 

 in microscopical sections of birds' kidneys. This process depends upon 

 Burian's reaction. The reagents employed must be carefully prepared 

 at the time of use. The section, fixed in alcohol and adherent to a cover- 

 slip, is washed in distilled water and dried. Two drops of a solution of 

 diazobenzolsulphonic acid are added. After half a minute, a further 

 quantity of the reagent is added, and then a small quantity of a sodium 

 hydrate solution. The reagents may also be used in the reverse order. 

 Yellowish-red points appear. The section may be mounted on a slide in 

 the excess of sodium hydrate, or in glycerin. In a section so treated, an 

 orange-red colour shows the presence of guanin in many of the cells of 

 the tubular epithelium and in the connective tissue. The guanin-free 

 portions have a pale yellow colour. Particulars of the stock solutions 

 required and the methods of preparation are given. 



Histological Changes in Infantile Paralysis. §— In the spinal cord 

 of an old standing case of infantile paralysis, V. Jonnesco has found a 



* Proc. Roy. Soc. Med., Pathol. Section iv. (1911) pp. 110-46 (26 figs.). 



+ Zeitschr. wiss. Mikrosk., xxvii. (1910) pp. 209-13. 



% Tom. cit.,pp. 257-9. 



§ C.R. Soc. Biol. Paris, lxx. (1911) pp. 109-10. 



