ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 459 



made experiments witli the object of ascertaining if in nutrient gelatin 

 which has been exhausted by the growth of some other Sohizomycete, 

 other kini^s of fission fungi, afterwards introduced, would develope. 

 Their results are as follows : — 



(1) Sp. cholerse asiaticee developed after M. tetragonus Pneiimonise, 

 swine erysipelas, pigeon diphtheria. 



(2) Sp. FinTileri after Emmerich's short rods, erysipelas, rabbit 

 septicgemia, M. tetragonus pneiimonise, swine erysipelas, pigeon diphthe- 

 ria, typhus abd. 



(3) Bacillus antliracis after erysipelas, rabbit septicaemia, M. tetra- 

 gonus pneumonise, swine erysipelas, pigeon diphtheria, and typhus abd. 



(4) Staphylococcus pyogenes citreus after Emmerich's short rods, 

 erysipelas, rabbit septiciaemia, M. tetragonus pneumonise, pigeon diphthe- 

 ria, and typhus abd. 



(5) Bacillus pyocyaneus after Emmerich's short rods, erysipelas, rabbit 

 septicEemia. M. tetragonus pneumonise, pigeon diphtheria, and typhus abd. 



(6) Bacillus prodigiosus after Emmerich's short rods, rabbit septi- 

 ca3inia, M. tetragonus, Staphylococcus fiavus, B. cyanogenes. 



(7) B. cyanogenes after B. typhi abd. 



Prevention of Cultivations from Drying.* — Dr. H. Plaut has found 

 that sterilized oil preserves cultivations from drying excellently well. A 

 flask of olive oil well plugged with cotton-wool is boiled, and when cold, 

 is poured over the cultivation so that it forms thereon a layer about a 

 finger's breadth deep. This procedure may also be adopted for cultiva- 

 tions which liquefy the medium, and does not prevent them from being 

 inoculated on others. 



(2) Preparing' Objects. 



Investigation of Cell structure.! — Herr G. P. Platner in his in- 

 vestigations on cell-division found that the best method of preserving 

 the subsidiary nuclei and their products is the use of osmic acid. The 

 degree of concentration of Flemming's acid mixture is quite sufficient if 

 allowed to act long enough. But as half an hour is not sufficient, and as 

 a longer period essentially afftcts the power of making sections, some new 

 method had to be adopted. Pieces of hermaphrodite glands cut up as small 

 as possible must be put fresh into the stronger of Flemming's mixtures, 

 and remain in it for an hour ; the solution must then be diluted with 

 three or four times its volume of water, and left to stand for twenty-four 

 hours. After careful washing, alcohol of increasing degrees of strength 

 may be added. The best staining material is h^ematoxylin prepared by 

 Apathy's method. The haematoxylin solution consists of 1 part of crystals 

 of haematoxylin, 70 parts of absolute alcohol and 30 of distilled water ; 

 the solution must be kept in dark vessels. The objects are stained in 

 toto for twenty-four hours. Then they are removed to 1 per cent, 

 alcoholic solution of bichromate of potasla for a day ; if lighter staining 

 be required, the objects must remain longer. Tlie objects were then 

 placed in 70 per cent, alcohol, and kept in it, in dark vessels, for several 

 days. Dehydration by absolute alcohol and use of cedar-wood-oil are 

 all that are now necessary. 



The specimens should next be imbedded in overheated paraffin for 



* Centralbl. f. Baktcriol. u. Parasitenk., v. (1880) p. 324. 

 i Arch. f. Mikr. Anat., xxxiii. (1889) pp. 126-7. , 



