44 LIFE, IN ITS LOWER FORMS* 



Pliny alludes to the Sponge as one of the articles used 

 by painters of his day : it has been conjectured from this 

 that water-colours were employed in ancient art, and the 

 Sponge probably performed a similar office to that which 

 it holds in the hands of a modern artist — 'washing out 

 lights, &c. 



In modern surgery, the use of the Sponge is great. The 

 flowing blood in operations is absorbed by it ; acrid dis- 

 charges from wounds and ulcers are thus imbibed ; and 

 dangerous hemorrhages are checked and sometimes 

 arrested by its application. The sponge-tent, formerly 

 much used for dilating sinuses and small openings, was 

 made by dipping the sponge into melted wax, and then 

 compressing it until it became cool, between iron plates.* 



The quality of bibacity in which the value of Sponge 

 chiefly consists, is owing to the multitude of minute 

 channels with which its whole substance is perforated, and 

 is dependent on the law of capillary attraction. By this 

 law fluids ascend, in tubes of small diameter, to a height 

 which increases in proportion to their tenuity, as any one 

 may observe who will plunge the end of a fine glass tube 

 into water. It is not requisite that the tubular form 

 should be perfect or uninterrupted ; the interspace 

 between two closely approximated fibres will serve as a 

 capillary tube ; and thus the sponge-fibres present a series 

 of canals, through which any fluid, with which a portion 

 of the surface is in contact, will continue to flow until the 

 whole are filled. 



A very different process is this spontaneous imbibition 

 of water by capillary attraction from that already de- 



* Pereira, Mat. Med. § 1814. 



