CHAPTER X. 



Respiration and Circulation— A Transparent Ascidia— Organs of 

 Sight— Play of the Gills— Ciliary Waves— The Heart— Cours- 

 ing of the Blood-globules — Reversal of the Current — "Na- 

 ture," what is it r — The Praise of God— Luminosity of the 

 Sea— A Charming Spectacle — Light-producing Zoophytes — 

 Luminosity a Vital Function — Noctiluca, a luminous Animal- 

 cule — Its Structure — Production of its Embryo — The Slender 

 Coryne — D escription — Parasites . 



RESPIRATION AND CIRCULATION. 



To take a stolen peep into the Adyta of nature's 

 mysteries, to surprise, as it were, life, carrying on its 

 more secret and recondite functions, must always afford 

 a peculiar pleasure to the reflecting and curious. This 

 the microscope often allows us to do ; and when our 

 eye is brought to the little dark orifice of the wonder- 

 shewing tube, we may fancy that we are slyly peeping 

 through the keyhole of Madam Nature's door, her 

 laboratory door, where she is actually at work, con- 

 cocting and fashioning those marvellous forms which 

 constitute the world of living beings around us. 



I have been for the last two or three hours engaged 

 in watching two of the most important vital functions, 

 respiration and circulation, under circumstances of 

 unusual felicity for the study. In looking over one 



