12 NATURALISTS' ASSISTANT. 



arsenical soap. The opening can then be covered with a bit 

 of goldbeater's skin. 



Exact labels giving the name of the bird laying the eggs, 

 the locality and date, the number of eggs in the nest, etc., 

 should be kept with each specimen and numbered to corre- 

 spond with a number placed on the egg. 



Eggs of our native birds taken at various stages of incu- 

 bation, the shell cracked and then the whole placed in 40 

 per cent, alcohol and in a few hours transferred to fresh and 

 slightly stronger spirit, and then after a day or two to alcohol 

 of 70 to 80 per cent., would 'be very desirable in every 

 museum of the world. Of course, with each egg should be 

 preserved not only the name of the species, but also the 

 number of hours since incubation began. Thus the student 

 will be able to trace more or less completely, according to 

 the amount of material at command, the development of the 

 various forms of which, at present, comparatively little is 

 known. The same process may be advantageously followed 

 with the eggs of other animals, and in dissecting mammals 

 all embryos should be carefully preserved. 



REPTILES AND BATRACHIA. 



The collection of snakes, turtles, lizards, frogs, toads, 

 and salamanders is not accompanied with any special difficulty 

 though proper precautions should be taken against venomous 

 serpents. Various species of each group affect certain lo- 

 calities, some living on land and others in the water. Some 

 live in the open fields, others in thick woods, while still others 



