ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 117 



down to 50° C. To this, one-third of its bulk of defibrinated rabbit's 

 blood, obtained aseptically, is added, and agar slants made. Loopfuls 

 of trypanosomatous rat's blood were sown in the condensation water, 

 and the tubes incubated at from 81° to 37° C. 



(2) Preparing: Objects. 



New Method of Preparing Superficial Fungi.* — H. H. Whetzel 

 has found the following method very useful for demonstrating the 

 presence of mycelium and pycnidia of fungi : (1) Peel or slice off a 

 piece of the epidermis on which the fungus is growing. (2) Immerse 

 the slice in a 2 to 4 p.c. solution of KHO, and boil in an evaporating 

 dish over a low flame for 20 to 30 minutes. Cook long enough to 

 remove all colour from the tissue of the host. (3) Pour off the 

 potassium hydrate, and wash by letting the material stand for 10 to 20 

 minutes in each of two or three changes of water. If all the colour 

 be not removed from the host tissue, cook again. Pick away any pieces 

 of sub-epidermal tissue that may cling to the epidermis. (1) Dehydrate 

 in 95 p.c. alcohol. (5) Clear in a mixture of two parts carbolic acid 

 and three parts turpentine. (6) Mount in balsam. 



The gist of the process lies in the fact that the pigment of the host- 

 plant is bleached by caustic potash, while that of the parasite is not 

 affected. 



Demonstrating the Statocysts of Cephalopods.f — R. Hamlyn- 

 Harris fixed and decalcified the material by immersion in sublimate- 

 acetic acid, though bichromate of potassium and acetic acid answered 

 perfectly well. Heidenham's staining method gave the best results, 

 though other stains were satisfactory. If the Statoliths were not 

 sufficiently decalcified the Statocysts were imbedded in celloidin, and 

 then decalcified with 1 to 2 p.c. hydrochloric acid. The celloidin was 

 afterwards dissolved out, and the preparations imbedded in paraffin. 



Detection of Tubercle Bacilli in Organised Sediment by means 

 of Centrifugalising or Simple Sedimentation.}: — C. Dilg gives the 

 results of a research chiefly on the specific gravity of the sputum in 

 relation to the position of tubercle bacilli in the tube of sputum after 

 centrifugalising, i.e. as to whether these bacteria are present in the 

 upper, middle, or deeper layers, as determined by the use of a capillary 

 pipette. In estimating the specific gravity of the sputum, it was first 

 rendered as air-free as possible by means of the air-pump, and then a 

 modification of the blood method of Hammerschlag employed, an 

 acetone-chloroform mixture being used. The specific gravity of the 

 tubercle bacilli, if in pure culture, was estimated in the same way. If 

 in sputum, it was held that if the bacilli were found copiously in the 

 middle layers of the tube of sputum after centrifugalising, then they 

 and the sputum were of the same specific gravity. By these means the 

 author found that the specific gravity of the sputum varied between 



* Journ. MyooL, ix. (1903) pp. 218-9. 



t Zool. Juhrb., Abt. f. Morph., xviii. (1903) pp. 327-58 (5 pis.). 



% Zeitschr. f. angew. Mikr., ix. (1903; pp. 141-55. 



