62 SEALE. 



and 1.5 meters deep. Its advantages are that it keeps the sponges clean 

 and it may be towed to any place ; its own weight sinks it sufficient!}' to 

 keep the sponges under water. 



The cleaning is greatly facilitated by frequently squeezing out the 

 sponges and a flat paddle of considerable weight may be used with good 

 effect. (Fig. 3.) A washboard made by tacking a cleat 2 centimeters 

 thick about 8 centimeters from each end of a wide board and then 

 stretching galvanized wire netting of 2 centimeters' mesh over the 

 cleats, tacking it to the ends of the board, is very useful. (Fig. 3.) 

 This instrument is especially useful to remove the dead, black skin from 

 the sponges. After five or six days in water, during which time the 

 sponges have been thoroughly squeezed, they are washed out in clean, 

 salt water and put in the sun to dry. They should still be kept in the 

 same position in which they grow, otherwise thej^ are apt to burn and 

 become red. However, the red color should not be confused with that 

 which many sponges naturally show in the center of their structure. 

 The sponges may be strung on stout twine about two meters in length 

 to facilitate handling them rapidh'. Salt water onlj^ is used in curing. 

 After the sponges are thoroughly dr}' they are ready to sack or bale for 

 market. Great care should be taken that the sponges are thoroughly 

 dry and clean, as the Philippine sponge can only oljtain the best market 

 if it is always shipped as a thoroughly cured, cleaned article. 



BLEiiCHING SPOKGES. 



Sponges are always shipped to the general marlcet in an unbleached 

 condition, but the following method by E. F. Bacon, of the chemical 

 laboratory, Bureau of Science, is very effective, doing the least damage 

 to the fiber: 



The sponges are placed in a saturated solution of potassium permanganate for 

 two minutes, then transferred to fresh water and thoroughly washed. They are 

 then squeezed out in a 10 per cent solution of sodium bisulphite until white; 

 then again thoroughly washed in fresh water until all the chemicals are removed. 

 They are afterward dried in the sun. 



CULTIVATION AND GROWING OF SPONGES. 



The growing of sponges for commerce has become established and 

 it promises to result in a profitable industry. 



Sponges are reproduced from eggs and by budding. The eggs are 

 formed and fertilized within the body of the sponge; they develop into 

 minute, free-swimming forms which are thrown out into the water 

 through the large openings. After about twenty-four hours the young 

 settle, become attached, and grow into separate sponges. Reproduction 

 by budding, however, is the metliod taken advantage of in growing 

 sponges from cuttings. The sponge should be placed on a wet board, 



