Journal of 



Applied Microscopy 



and 



Laboratory Methods 



Volume V. 



OCTOBER, 1902. 



Number 10. 



A Macroscopical Mount for Museum and Class 



Work. 



Every modern instructor in zoology knows the advantage of having numer- 

 ous prepared specimens for demonstrations. Glass bottles and jars serve well 

 enough for some wet specimens, but in many cases the details of feature and 

 structure are largely obscured 

 by the reflection and refrac- 

 tion of light caused by the 

 shape of the receptacle con- 

 taining the specimen. Even 

 the rectangular jars so often 

 used are objectionable on ac- 

 count of their cost, and also 

 because they do not easily 

 permit the arranging of a 

 series of specimens in order. 



Therefore the method of 

 using a square piece of glass 

 as the base and a watch 

 crystal as the cover has been 

 devised. The material to be 

 mounted should be dissected 

 or fixed in shape for demon- 

 stration, and then fastened to 

 the square of glass with a 

 few drops of a solution made 



by dissolving ten grams of gelatin in 60 c. c. of hot water. The gelatin will harden 

 sufficiently in about fifteen minutes so that the specimens thus arranged may be 

 immersed in five per cent, formalin, and all sediment carefully washed away. 



(1989) 



Fig. 1. — Photograph of the parasitic crustacean of the cod 

 Lernea branchialis, as seen in the crystal mount. 



