132 SPECIFIC EXAMPLES OF SLIDE-MAKING 



The only difficulty of the procedure consists in persuading each section to 

 occupy its correct place on the slide. This is carried out most easily by the 

 following technique. A single slide is taken, placed in front of the operator, 

 and covered lightly with the diluted adhesive. The fluid should extend to the 

 edge of the slide but should not be raised in a meniscus sufficiently high to 

 cause any appreciable slope of the fluid from the center of the slide toward 

 the edges. Using a sharp scalpel, the end section is cut, with a rocking motion, 

 from each of the ribbons. These sections are placed in the correct order but 

 without any regard to symmetry on the surface of the fluid on the slide. To 

 secure these sections in the required position, it is necessary to have two fine 

 brushes, a mounted needle, and a bunsen burner or spirit lamp. 



The last section (that is, that section which is to lie farthest from the label 

 on the slide) is now secured in position with a brush held in the left hand, 

 while the second section is maneuvered with a brush held in the right 

 hand until its edges touch those of the first section. Both sections will be held 

 together by capillary attraction when the brush is removed. The needle is 

 warmed in the flame and used to fuse the edges of the sections together in 

 two spots. If the entire edge is melted, it will cause a ridge which will prevent 

 the compound ribbon from lying flat against the slide; two minute spots fiased 

 together with the point of the needle are sufficient to hold the section in place. 

 The needle is laid down, and the brush again picked up with the right hand 

 and used to guide the next section into its appropriate place. This section is 

 spotted into position with the tip of the warm needle, and so on, until all the 

 sections have been fused into a continuous ribbon. Then the slide is placed in 

 the usual way upon the warm table until such time as the ribbons have flat- 

 tened; they are drained in the manner described under the section on section 

 cutting technique and then pressed to the slide with a wet filter paper and 

 rubber roller, if this is the method of operation preferred by the technician. 

 The compound ribbon, of course, may be guided into the center of the slide, 

 while the latter is still wet, before it is pressed or dried. The sections are left, 

 in the ordinary course of events, on the warm table until they are entirely dry 

 before being dewaxed in xylene and brought down to 90 per cent alcohol 

 through absolute alcohol in the usual manner. 



Ehrlich's acid alum hematoxylin has been selected for this typical example 

 because it is one of the best, though at the same time one of the most fre- 

 quently misused, of the hematoxylin stains. The method given for its prep- 

 aration should be rigorously followed; that is, the hematoxylin should be 

 dissolved in a mixture of acetic acid and absolute alcohol, and then the glyc- 

 erin, water, and ammonium alum should be added to the bottle, which should 



