The Zoologist — September, 1873. 3665 



Coming down to later times, we find that in 1743 our countryman 

 Baker distinctly represented specimens of Hydra viridis kept in 

 water in an upright glass vessel. 



It appears from the works of Esper, published continuously from 

 1771 to 1784, that that distinguished entomologist constantly kept 

 aquatic insects in water: he has given us most interesting par- 

 ticulars concerning them, and seems to have been delighted in 

 observing their longevity in confinement ; he particularly mentions 

 a male individual of Dytiscus marginalis, a carnivorous water beetle, 

 that lived three years and six months in his aquarium ; and James 

 Francis Stephens many years subsequently, commenting on this 

 seemingly extraordinary fact, attributes this prolonged life to 

 enforced celibacy. Esper has left no record, so far as I am aware, 

 of the plan or principle of his aquarium, and I believe only this 

 single record of his success. 



Simultaneously with Esper, Gilbert White seems to have utilized 

 the aquarium for observation : the first edition of his ' Natural 

 History of Selborue,' printed in 1789, but written in 1781, has the 

 following passage :^" When I happen to visit a family where 

 gold and silver fishes are kept in a glass bowl, I am always pleased 

 with the occurrence, because it offers me an opportunity of ob- 

 serving the actions and propensities of those beings with whose lives 

 we can be little acquainted in their natural state. Not long since 

 I spent a fortnight at the house of a friend, where there was such a 

 vivary, to which I paid no small attention, taking every care to 

 remark what passed within its narrow limits." This great naturalist, 

 for great he really was in his singular acuteness of observation and 

 scrupulous truthfulness of narration, thus utilized an aquarium, 

 although calling it by another name : his observations on the 

 manner of death in fishes, on the structure of their eyes, and on 

 their mode of progression, the pectorals being employed for gentle 

 motion, and the caudal for " shooting along with inconceivable 

 rapidity," show to what good purpose he devoted these oppor- 

 tunities of observing. 



I have met with no evidence of experiments or arrangements 

 of the same kind until, in 1830, my esteemed and respected 

 friend James Scott Bowerbank, then residing at No. 19, Critchell- 

 place. New North-road, continuously and successfully utilized the 

 aquarium in his researches into the " Circulation of the Blood in 

 Insects." Of all investigators I ever knew, Dr. Bowerbank was the 



