Journal of Applied Microscopy. 



169 



A Rapid Staining Apparatus. 



Methods of staining may be roughly- 

 arranged in three classes: staining in 

 toto, staining the sections and carrying 

 them through all the steps necessary 

 previous to mounting them in balsam on 

 the slides, and, finally, performing all 

 the work of staining after the sections 

 have been fastened to the slides. 



Fig. 1. 



The first method is an excellent one, 

 when small pieces of tissue are used. 

 Large pieces would not be penetrated 

 evenly by the staining agent. This 

 method is very rapid; for the sections 

 can be mounted directly from the knife 



ssQ- 



pieces of firm, homogeneous tissue, such 

 as pieces of liver, are employed, and in 

 case it is not necessary to preserve the 

 continuity of the series of sections, 

 good results may be obtained by placing 

 the sections as soon as cut in watch 

 glasses, filled with the proper reagents. 

 By transporting them from one dish to 

 another by means of a section lifter, or 

 even by means of a glass rod, the sec- 

 tions may be carried through the various 

 processes necessary to prepare them for 

 mounting, before they are placed upon 

 the slide at all. 



This method is entirely inapplicable to 

 serial work, as in embryological investi- 

 gations for instance. Only firm struc- 

 tures could be treated in this way, for 

 the more delicate ones would rapidly go 

 to pieces, after the removal of the par- 

 affin, without something to hold them in 

 place. Even firm tissues are in great 

 danger of being torn and distorted, or 

 entirely destroyed, by being so often 

 handled. Thus it appears that, for work 

 In which delicate structures are involved 

 or for pieces of considerable size, both 

 the above methods fail. 



To meet these difficulties, the method 

 of staining on the slide has been re- 

 sorted to. As applied in the laboratories 

 of Cornell University, the method is as 

 follows: the sections are fastened to the 

 slide by means of a thin coat of albumen 

 and heat, if embedded in paraffin, or by 

 a drop of ether-alcohol, if collodion is 

 used. After the removal of the paraffin 

 or the oil by means of benzine or xylene, 

 they are treated with ninety-five per 

 cent alcohol. They are now ready to be 



Fig. 2. 



in Canada balsam after removing the 

 paraffin, or, in case the object is im- 

 bedded in collodion, it is only necessary 

 to remove the oil, dehydrate, clear, and 

 mount. On account of the difficulties in 

 securing good penetration of the stain- 

 ing fiuids, this very efficient method has, 

 we are loath to note, a rather limited 

 application. 



In most cases better results are ob- 

 tained by staining after the sections are 

 cut. As was suggested above, this re- 

 sult may be obtained in two ways. When 



stained. The slides may now be placed 

 either in the ordinary Stender dish, 

 containing the staining agent, or laid 

 flat on the rack (r. Fig. 5) over the waste 

 jar (w, Fig. 5). In the latter case, the 

 staining agents are poured upon the 

 slides by means of pipettes. Excellent 

 results are uniformly obtained in this 

 way, in serial as well as single sections. 

 Since the section is firmly fastened t.o 

 the slide, the relative position of the dif- 

 ferent parts of the tissue is not changed, 

 and the section does not become broken. 



