ZOOLOGY. 127 



mere accumulating a large variety of curious species that 

 the science is advanced, but it is by acquiring a knowledge of 

 the habits and propensities, the contrasts, the similarities, the 

 uses or injuries they offer to mankind, that gives life and 

 spirit to the science ; and in fact is the true and only real 

 use of the study. 



When a new species is observed, both sexes if procurable 

 should be obtained, with their nests and eggs ; notes should 

 be taken of what places the kind resorts to, if its nest be 

 placed in a tree, a hole in the ground, or if the eggs are 

 deposited without a nest ; the number, colour, and size of 

 the eggs ; the substance of which the nest is composed should 

 also be remarked, as frequently, when almost every exter- 

 nal mark would seem to warrant the blending of two species 

 in one, the shape, or the material, of which the nest is 

 formed, will afford excellent specific characters ; as it is a 

 rule to which we know of no exception, that each species 

 builds its nest with the same kind of materials, and places 

 It in similar situations in all countries. The food of the 

 species, its time of incubation, its term of life ; at what time 

 of the year it migrates, and for what period, should, if pos- 

 sible be learnt. 



In such cases as v/ill admit, the nest and eggs should be 

 preserved, the nest being first thoroughly dryed and baked ; 

 the eggs should be carefully blown, noticing if any material 

 change is made in the apparent colour of the shell, by the 

 absence of the yolk, &c. Eggs require considerable pains 

 to preserve them whole, as unless the apperture at each ex- 

 tremity is made perfectly round without cracking the edges 



