TEREDO NAVAI.IS AND OTHER SEA-WORMS. 197 



severely from damage by the Teredo. Until tlie year 1890, the 

 water of the Old Port was certainly, as it now is, warm ; but the 

 port was then receiving all the filth of the town, which overlooks 

 and partly encloses it. The few sewers that then existed dis- 

 charged into the port, and secured its immunity from the Teredo, 

 which could not live in its polluted and evil-smelling water. 



In 1890 new sewers, which left the water of the port 

 almost uncontaminated, were constructed ; but this advantage 

 is now heavily outweighed by the damage caused by 

 Teredo. In 1895, that is some four or five years after the con- 

 struction of the new sewers, its depredations became apparent, 

 all the lighters not sheathed in zinc being simultaneously 

 attacked. Specimens of silver fir, pine, and oak timber, 

 obtained from this port, prove the terrible activity of this borer, 

 which has literally riddled the wood and reduced it to one-half 

 of its original solid volume. 



M. Henry quotes from an article in the BuUeiin de la 

 Marine luarchande, by M. A. Cligny, Director of the Station 

 aqjiicole at Boulogne-sur-Mer, who states that the Teredo appears 

 to be much less abundant in that port now than formerly. Cold, 

 he says, destroys the pest, which is hardly to be found during 

 winter, especially during rigorous seasons, and similar observa- 

 tions have been recorded in northern countries. 



Is it necessary, asks M. Henry, as some think, to abandon 

 the use of wood in ports, and to substitute metal or ferro- 

 concrete, notwithstanding that these substances have already 

 disappointed the expectations formed regarding them, as thfey 

 do not possess the suppleness, elasticity, and tenacity which 

 renders timber so valuable in such situations? It is universally 

 held to be preferable to continue the use of timber, which is 

 superior to all other substances. 



And again — is it necessary, in order to protect timber from 

 the Teredo, to coat it with a costly metal cuirasse? Not at all ! 

 We know that it can be protected from attack by fungi and 

 insects of all sorts by means of antiseptics penetrating its entire 

 substance; and why should not similar measures be adopted 

 against the Teredo ? 



As may be supposed, all possible methods of coating and im- 

 pregnation have been tried. "None of them" (says M. Cligny) 

 " is completely efficacious. The injection of creosote and 

 creosoted oils confers but a precarious immunity, which is hardly 



