1072 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in this solution for 12 to 24 hours, and according to its intensity tho 

 colour is extracted by acetic acid, or water acidulated with acetic 

 acid. The sections are then to be washed and examined in glycerin, 

 but permanent preparations are mounted in balsam. Over-staining 

 with osmic acid is removed with peroxide of hydrogen. 



Preparing the Iris.* — Dr. O. Eversbusch employs the following 

 contrivance for examining the muscular tissue of the iris in 

 Mammalia. 



Liver, amyloid for choice, is hardened for five weeks in Midler's 

 fluid, and after careful and prolonged dehydration in alcohols (up to 

 absolute) is passed through, seriatim, the alcohol-clove-oil mixture, 

 oil of cloves, turpentine, paraffin mixture, and lastly Merck's paraffin. 

 Then a piece about ■ 5 cm. thick is imbedded in a composition of 

 hard and soft paraffin, and having been placed on a microtome 

 (Katsch) is planed smooth. On this smooth surface tho iris soaked in 

 paraffin is placed and covered with fluid paraffin. 



The author recommends that the iris should be stained in toto, 

 and advises picrocarmine, hematoxylin and Grenacher's alum-carmine, 

 giving preference to the last. If the preparation be too highly 

 coloured the nervous elements are liable to be confounded with the 

 muscular ; therefore the tint should not exceed a light rose. 



Preparing Spinal Ganglia of the Frog.j — Dr. M. von Len- 

 hossek recommends the ganglia, of which the seventh, eighth, and 

 ninth are easiest of access, to be placed in a 1 to 1 • 5 per cent, osmic 

 acid solution, wherein they remain for three-quarters of an hour. 

 Preparations were made both by section and teasing out. The 

 hardened objects were imbedded either in Flemming's transparent 

 soap or in Schiefferdecker's celloidin. Dissociation of the ganglia 

 exposed merely to the influence of osmic acid did not produce satis- 

 factory results. The author recommends objects treated with osmic 

 acid to be placed afterwards in a mixture of equal parts of acetic acid 

 and glycerin. The action of the acetic acid on the interstitial tissue 

 may be increased by exposing the fluid with the ganglia for a day to 

 a constant temperature of 35°-40° C. 



Preparing Eyes of Heteropoda.J — Dr. H. Grenacher recommends 

 for the preservation of the eyes of Heteropoda, when intended for after 

 examination, the use of Kleinenberg's picro-sulphuric acid mixture. 

 A mixture of picro-sulphuric acid with sublimate, which had been so 

 useful in the examination of retina of Cephalopoda, was here useless. 

 The employment of the former medium with consecutive extraction 

 with alcohol, led through irregular crumpling to destruction of 

 opposing layers of single parts, occasionally to loss of continuity. 



For the removal of pigment, Grenacher uses the hydrochloric acid 

 which rendered good service in the Cephalopoda (2 or 3 parts to 100 



* Deutsche Zeitschr. f. Thiermed. u. Vergl. Pathol., xi. Zeitschr. f. Vergl. 

 Augenheilk., iii. (1S85) pp. 25-32. Cf. Zeitschr. f. Wiss. Mikr., iii. (1S86) 

 pp. 251-2. 



t Arch. f. Mikr. Anat., xxvi. (1886) pp. 370-453 (2 pis.). 



t Abh. Naturf. Gesell. Halle, xvii. (1886) 64 pp. (2 pis.). 



