702 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



B. Technique.* 



2) Preparing- Objects. 



Effects of Pyridin Fixation upon Nervous Tissues.! — A. Montanari 

 has made observations upon the effect of this fixative upon the cells of 

 the medulla. Following Donaggio's method, he put portions of the tissue 

 into the fixing reagent for varying periods of two to seven days, treated 

 them with the mordant, ammonium chlor-molybdate, and stained with 

 thionin. He found that there was a marked difference between the 

 appearance of the cellular structure in those portions 

 that had been in pyridin for two days, and in those that 

 had been exposed to the action of the fixative for longer 

 periods. He describes the appearances successively of cells 

 which had been fixed for two, three, four, and so on up to 

 seven or more davs, and traces the changes from a first 

 period of spongy vacuolation through an intermediate 

 stage, showing a false network to a final form in which a 

 true network with monilif orni septa is seen. Concurrently 

 with these reticular changes, an alteration in the be- 

 haviour of the nuclei towards the stain is observed. 

 The author considers that this work may have a bearing 

 upon the question whether the fibrillation of nervous 

 cells is to be regarded as an artefact. 



Simple Washing Apparatus. J — E. Schaffnit has 

 devised the simple piece of apparatus shown in fig. 86. 

 To a water-tap is attached by means of rubber tubing a 

 filter funnel or flask, from which the bottom has been 

 removed. The open end of this vessel is covered with 

 fine silk, fixed round the edge. Portions of tissue to be 

 washed are introduced either through the neck or 

 through the open end before fixing the silk membrane. 

 Before turning on the water the flask is placed in a 

 horizontal axis and half filled with water ; then it is 



Fig. 86. restored to its normal position, and as the water 



continues to flow, the air pressure maintains it at a 



constant level. To remove the smaller portions of tissue, when washing 



is complete, the rubber tube is removed, and the flask immersed in water, 



so that the material floats through the neck. 



Simultaneous Fixing and Staining.§ — F. Strecker comments upon 

 the advantages, for histological purposes, of using solutions in which 

 the fixing and staining agents are mixed. After a concise resume of the 

 methods and formulas recommended by various workers, he points out 



* This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects ; (3) Cutting, including Embedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including slides, preservation fluids, etc. ; 

 (6) Miscellaneous. 



t Zeitschr. wiss. Mikrosk., xxvii. (1911) pp. 22-25. 



X Zeitschr. wiss. Mikrosk., xxviii. (1911) pp. 49-50. 



§ Zeitschr. wiss. Mikrosk., xxviii. pp. 17-21. 



