118 THE MICROSCOPE. 



rigidity. Ruysch (from whom the art of injecting has 

 been called the Ruyschian art) recommends a previous 

 maceration for a day or two in cold water. 



The size must always be kept hot with the aid of warm 

 water; for if a naked fire be used, there is danger of 

 burning it. The size may be placed in a vessel which can 

 be heated by standing it in a common tin saucepan of hot 

 water. A convenient form of apparatus for melting the 

 size, and afterwards keeping it at a proper temperature, is 



Fig. "if. Melting Vessel. 



shown in fig. 77. It consists merely of a water-bath, in 

 which the cans containing the injecting fluid can be kept 

 hot, and their contents protected from dust by means of 

 their covers. A small apparatus of this kind could be 

 made by any tin-worker, and fitted over a gas jet to stand 

 on the table. 



The operator should be provided with several pairs of 

 - strong forceps, for seizing the vessel or stopping the escape 



Fig. 78. 



of injection. A small needle, fig. 78, will be found useful 

 for passing the thread round the vessel into which the 



