248 SUMMAEY OF CUKRENT RESEARCHES RELATING TO 



vessels. They may be studied in water or mounted in balsam. The 

 author examined his preparations under a Zeiss binocular stereopticon 

 Microscope. 



Studying Phagocytoses in Frogs and Insects.* — L. Mercier, when 

 studying the phagocytic processes during the metamorphosis of Batrachia 

 and insects, adopted the following procedure. Sterilised powdered car- 

 min was injected into the dorsal lymphatic sac of four adult frogs. 

 Next day pieces were cut off the tail of young tadpoles still devoid of 

 feet, and these pieces were introduced into the lymphatic sacs of the 

 frogs which on the previous day had received the carmin injection. 

 On the third, fifth, sixth and eighth subsequent days the frogs were 

 killed : lymph was removed from the sacs by means of a pipette, placed 

 on a slide, and fixed by heat. The films were stained with hematoxylin 

 and eosin. The fragments of the tails found in the sacs were fixed in 

 sublimate, and the paraffin sections made therefrom were stained with 

 iron-hfematoxylin and eosin. The technique used in the case of the 

 Muscidffi was on similar lines to that used for the frogs. The insects in 

 the nymph stage were injected v.ith the carmin solution by means of a 

 very fine glass tube. The larvae were first fixed by immersion in water 

 at 72° ; the animals were then cut open either longitudinally or trans- 

 versely, and placed in sublimate or in Bouin's or Flemming's fluid. 



Injecting- Liver.t— P. T. Herring and S. Simpson, for their study 

 of the relation of the liver-cells to the blood-vessels and lymphatics, used 

 a carmin-gelatin mass made' according to Carter's formula. The solu- 

 tions of gelatin and ammoniacal carmin were filtered separately and very 

 carefully, then mixed and rendered slightly but distinctly acid with 

 acetic acid. During the operation the injecting apparatus was kept 

 immersed in warm water. The pressure was indicated by means of a 

 mercury manometer. The cannula was inserted in the aorta or the portal 

 vein. In the former case the inferior vena cava was opened above the 

 diaphragm, and in the latter the inferior cava was ligatured below the 

 liver. A preliminary washing out of the blood-vessels with physiological 

 saline was found to be unnecessary. The pressure employed varied from 

 60-160 mm. of mercury, when the injection was made through the aorta, 

 and rarely exceeded 20 mm. of Hg when made from the portal vein. 



When injection was completed, the liver was removed if the animal 

 was large ; if small, the abdomen and thorax were freely opened, and the 

 whole animal placed at once in 10 p.c. formalin, with some ice added. 

 "When the gelatin had set the liver was removed and cut into pieces, and 

 put back into 10 p.c. formalin. When thoroughly fixed the pieces were 

 dehydrated and paraffin sections made. These were lightly stained with 

 h^ematoxylin. Deep staining stains the gelatin and masks the carmin. 



(5) Mounting-, including Slides, Preser^rative Fluids, &c. 



New Dehydrating Apparatus. J — A Greil describes an apparatus 

 suitable for dehydrating delicate embryological and histological material. 



* Archiv Zool. Exp6r., v. (1906) pp. 1-151 (4 pis.). 



t Proc. Rov. Soc, Series B, Ixxviii. (1906) pp. 455-97 (2 pis.). 



X Zeitschr." wiss. Mikrosk., xxiii. (1906) pp. 286-301 (4 figs.). 



