a Kational Museum, 303 



female. This is requisite in a state in which it is ordained 

 that subsistence shall depend upon exertion : for during the 

 period of parturition, &c., it is necessary that the strength 

 of the male should be exerted for the maintenance of both. 

 The difference between the ^itrength of males and females 

 will be found generally proportionate to the different degrees 

 in which such necessity shall be found to exist. 



The teats of femalea of different species are adapted in 

 size, form, situation and number, to their respective young. 

 ** At the moment the young animal enters into the world, 

 its maintenance, the maternal milk, is ready for it." 



The new-born child is without teeth. " It is evident that 

 the act of sucking will be performed with more case, both 

 to the mother and infant, while the edges of the gums are 

 snmoth and soft, than when they are bordered with sharp 

 hones. Bv the time they are wanted the teeth are readv." 



The remarkable increase of ingenuity and courage in njost 

 brutes during the tender and defenceless state of their young, 

 appears to be a relation of instinct. This impulse of instinct 

 guides the sexes of all species, directs the young to the 

 teat, induces birds to build nests, and brood on their eggs, 

 urges fish from salt to fresh water, and insects to provide fora 

 progeny of which they never live to see the birth. — Ch. xviii. 

 k. Relations of animals to food, and food to animal*. 

 Specimens of teeth, bill, gizzards, and stomachs. 



The teeth of animals are adapted to the mastication of 

 varieties of food. Where long- continued mnstication and 

 trituration is requisite, the teeth are broad and solid; Vvhere 

 less comminution is needful, thev are hollow and sharp. 

 *' 'J'he gastric juice of birds of prey^ of an owl, or a kite, 

 acts upon animal fibre alone, will not act upon seed and 

 grasses at all. The gastric juice of ruminating animals, as 

 the sheep and the ox, speedily dissolves vegetables, but makes 

 no impression u^on animal bodies." 'I'he construction of 

 the stomachs of runnnaling anin)als differs considerably 

 from that of animals which require anin)a] food. Birds 

 furnished with soft bills are provided with gizzards neces- 

 sary to triturate their grain. Those which possess hard, 

 strong, and hooked bills and claws, whose gastric juices 



will 



