206 Transactions of the 



cabinet, with other objects, and watered for examination when 

 required, or, as a rule, once a month : so small a quantity of water 

 dries up rapidly in summer; in a day sometimes. The longest 

 time it has kept continuously dry is ten months ; in winter, after 

 watering, it has been frozen into a mass of ice ; it has been heated 

 on a brass mounting-table, with a spirit-lamp very often, in order 

 to melt the marine-glue when a new cover has been required; it 

 has been exposed dry to the sun in a photographer's glass room, all 

 through a broiling summer ; taken a sea voyage to the south of 

 Spain, revived there, and brought home again ; taken to Ceylon ; 

 to India; revived on ship-board, to the astonishment of the 

 passengers ; brought home, and a few of the dry inhabitants 

 immediately posted off again to a friend in Ceylon, who revived 

 and has them still. As a final indignity and injury this much- 

 enduring family has been put into the receiver of an air-pump for 

 twelve hours and thoroughly exhausted. This was almost too 

 much for it, but still there is a little life in the tank. 



Eecently I determined to make a methodical series of experi- 

 ments, to see if any new light could be cast on what I thought 

 were disputed points regarding the perfect drying and revival of 

 certain rotifers, but reference to books, old and new, soon proved 

 that now at least there was no disputed point at all. The battle 

 had been fought and won, and controversy ended. As a matter of 

 history it had a certain interest to know how Spallanzani and 

 Doyere experimented and Ehrenberg doubted, but it is far more 

 interesting to learn the ultimate result as recorded unanimously by 

 our modern text-books. Thus, Pritchard*: — "They have the 

 power of preserving their vitality when thoroughly desiccated. 

 Leuwenhoek and Spallanzani experimented on them, and announced 

 the fact of their revivification on the addition of moisture months 

 and even years after their complete desiccation. Schrank, 

 St. Vincent, and Ehrenberg questioned the truth of the state- 

 ment. . . . Schultze and Doyere have repeated and confirmed the 

 experiments of the old observers, and the latter authority concludes 

 that Eotifera may be completely dried in a vacuum without losing 

 the capability of being revived by moisture. Many, indeed, are 

 sacrificed in the process, but enough recover to demonstrate the 

 possibility of the fact." 



And what does Dr. Carpenter say ? " Certain f Eotifera are 

 remarkable for their tenacity of life, even when reduced to a most 

 complete state of dryness ; for they can be kept in this condition 

 for any length of time, and will yet revive upon being moistened. 

 Experiments have been carried still further with the allied tribe of 



* ' History of Infusoria,' 4th edition. 



+ ' The Microscope and its Revelations,' 4th edition. 



