86 SPECIFIC EXAMPLES OF SLIDE-MAKING 



slide. It is then easy to arrange the parts with needles, but it is difficult to 

 lower a second slide without disarranging these parts. An alternative method 

 is to place the slide with its coverslips in the finger bowl with the specimen, 

 to arrange its parts under water, and to place the second slide on top. Which- 

 ever process is adopted, the slides are tied or clipped together and transferred 

 to a jar of 96 per cent alcohol where they may remain for a week or until next 

 required. Each specimen is treated in this manner. It is better not to try to 

 flatten two or three specimens on one slide. 



When it is time to continue mounting the specimens, the slides are placed 

 in a finger bowl of 96 per cent alcohol before cutting the cords or removing 

 the clips which bind them together. Getting the two slides apart without 

 damaging the specimen is not easy, particularly if the specimen tends to stick 

 to one or the other of the slides. The simplest method is to insert the blade 

 of a scalpel into the gap between the slides and twist it slightly to see whether 

 or not the specimen is free. If the specimen shows signs of sticking to one 

 slide, the other may be removed, and the specimen washed from the slide to 

 which it is stuck with a jet of 96 per cent alcohol from a pipette. If it shows 

 signs of sticking to both slides, it is still possible to free it from both by pro- 

 jecting a jet of 96 per cent alcohol between them. Each slide is treated in due 

 order until one has accumulated all the flattened specimens in a dish of 96 

 per cent alcohol. It must be understood that these specimens have been hard- 

 ened flat, so that no amount of subsequent treatment will ever swell them out 

 again or prevent them from remaining in the required position. 



It is recommended, if one has several specimens to handle, that a series of 

 the little cloth-ended tubes shown in Figure 9 be used. The only alternative is 

 to handle each specimen with the aid of a section lifter with the consequent 

 risk of damage. Though not nearly so satisfactory, it is also possible at least 

 for the process of staining and dehydration, to place all the specimens in a 

 small vial in which the different fluids used may be placed successively. 



A wholemount of this type is best stained in carmine, and the choice would 

 lie between Mayer's carmalum and Grenacher's alcoholic borax carmine; the 

 author's preference is for the latter. The preparation of the latter stain, the 

 formula for which is given in Chapter 2, does not present any difficulty, but 

 it should be noted that a differentiating solution of 0.1 per cent hydrochloric 

 acid in 70 per cent alcohol will be required. Adequate supplies of this should 

 be available before one starts staining. 



The specimens are now passed from 96 per cent alcohol to 70 per cent 

 alcohol. Naturally, they will float, but, as soon as they have sunk to the 

 bottom, it may be presumed that they are sufficiently rehydrated. Either the 



