58 COMPARATIVE ANATOMY 



contracting the surrounding muscles, the throat and 

 mouth can easily be cleared of the fluid. The spi- 

 racles, moreover, have a secretion peculiar to them- 

 selves ; and it is now the fashionable opinion among 

 naturalists, that it is especially this secretion, toge- 

 ther with the superfluous vapour of the lungs, which, 

 along "with the expired breath, forms the proper 

 substance of the projected column. This is the 

 opinion maintained, among others, by Scorseby and 

 Blainville, certainly weighty names. Notwithstand- 

 ing this, we venture to express doubts whether 

 the point is either definitely or satisfactorily esta- 

 blished. It would appear there is an allowed dif- 

 ficulty, arising from the great quantity of the fluid 

 frequently expelled ; which is met by the statement, 

 that sometimes the ejected air comes in contact with 

 some supernatant water, and raises quantities along 

 with it. With a perfect cognizance of these opinions, 

 however, we find that M. Lesson, from much per- 

 sonal observation, dissents from this opinion, and, 

 as late as 1828, maintains the old and now often 

 scouted explanation. He states that, from having 

 often seen the phenomenon, and fi*equently within 

 the distance of a few yards, he feels constrained to 

 oppose the prevailing view. He observes of the 

 sperm whale, that when only breathing, and not 

 feeding, it has no jets at all; and that, when feeding 

 and taking in water, it then expels some through its 

 spiracles, though to no great height ; whilst in other 

 whales, the projected column long retains the appear- 

 ance of a united stream, mounting high before it 



