6436 



Reason and Instinct. 



in view. The cultle fish in discharging its ink must be guided by 

 some sort of judgment ; the garden snail, too, which not only retreats 

 into its shell at the approach of apparent danger, such as the adhibition 

 of the finger or other object, but after a pause issues and seems to be 

 occupied in investigating the cause of disturbance, if it be still near 

 but not actively offensive. 



Our next step in advance brings us to the class of Fishes. Among 

 these, universally, the mass of the brain is very small in proportion to 

 the mass of the body, though the proportion is an exceedingly variable 

 one ; but still the encephalic mass consists of more parts, and those 

 parts comparatively more developed. There is a cerebellum in addition 

 to the spinal cord and medulla oblongata ; and besides this, the optic 

 lobes are well defined, and there are what appear to be rudimentary 

 cerebral hemispheres ; while in some, olfactory nerves are found also. 

 Endless variations in relative size of these several ganglia are also 

 found, as well as the variations of total size of brain already referred 

 to, many of which already admit of illustration in the habits and pecu- 

 liarities of the several fishes concerned, and about which no doubt 

 progressive physiological and Natural History discoveries will reveal 

 much more before long ; but, on the whole, it is an unquestionable 

 fact that the brain in the class of fish is, in respect of contrivance and 

 development, an advanced and advancing organ. And on the other 

 hand Instinct and Intelligence both keep pace, speaking generally, 

 with the ascertained advance of the mental organ. The former operates, 

 taking the class as a whole, in most of its accustomed channels, — power- 

 fully in some. As cases in point I may cite the parental affection of 

 some species for their ova or young ; the strong evidences of the 

 operation of the instinct of sexual love, which the history of others 

 affords ; the return to their breeding streams of others again ; and the 

 periodical arrival at, and passage beyond given points, of inexhaustible 

 shoals of other varieties ; and so on. In fact, the increased operation 

 of Instinct in fishes is too evident to require more than passing notice 

 or illustration ; and, moreover, in strict analogy with the advanced 

 organization of the brain, we find marked advances in Intelligence or 

 towards Rationality in all the varieties of fish with which we have 

 anything like a sufficiently intimate acquaintance. Thus, some of 

 them are known to recognise sounds, and to connect with the sound 

 the idea of food ; some have recognised persons even, manifesting no 

 great unwillingness to be even handled by some favoured one, but 

 carefully avoiding familiarity with strangers ; they certainly learn by 

 experience, as in the case of the artificial fly, which is eagerly seized 



