1902-3] Sawdust and Fish Life. 459 



Four days after this, black bass fry placed in the upper fourteen 

 inches lived only about one hour. They also swam along the surface 

 and appeared to be gasping for air. That they were suffocating in both 

 cases was proved by the fact that when fry were placed in a wash bottle 

 of this water with air bubbling through it, they lived on for twenty-four 

 hours, and were then apparently well and exceedingly active. On being 

 transferred from the wash bottle to the aquarium the animals at first 

 plunged downwards to the bottom, paused there a moment, but soon 

 came towards the surface breathing very rapidly. Evidently they were 

 suffering from lack of oxygen. They swim along the top with noses 

 upwards and body inclined at an angle of about thirty degrees with the 

 surface. Gradually they tire ; sink towards the bottom ; rise again ; 

 swim convulsively towards the surface ; jump clear out of the water with 

 gaping mouth ; become exhausted by their convulsive efforts and finally 

 sink to rise no more. Of all the fish killed in this extract not one ever 

 rose to the surface after death. 



It would be difficult to say whether this experiment throws any 

 light upon a point much discussed in the literature of sawdust. The 

 point is this : if sawdust kills fish, why are they not found dead in con- 

 siderable numbers along the course of the stream ? In my experiments 

 the dead bodies of the fish never rose out of the poisonous liquid. 



Aromatic Compound. 



The foregoing experiments show that the oxygen naturally dis- 

 solved in the upper fourteen inches of water had, at the end of a week, 

 all disappeared. It was used up either in supporting the life of the 

 bacteria, or in oxidizing the wood extracts through the agency of the 

 bacteria. Bacteria were abundant in every part of the aquarium, but 

 especially in the underlying solution. Moreover, either by their action 

 on the pine extracts, or by the chemical decomposition of these extracts, 

 an aromatic compound of a sweetish pleasant smell had begun to form. 

 At the surface the smell was faint ; but in the water siphoned off from 

 the bottom the perfume was strong and agreeable. The production of 

 this compound is possibly due to micro-organisms, and if the special 

 bacterium could only be isolated and used upon the extracts without 

 admixture with other forms, it might be possible to manufacture a per- 

 fume from pine which many people would find agreeable. Alcohol, 

 lactic acid, acetic acid, etc., are all formed by the action of bacteria upon 

 vegetable substances in solution ; the quality, too, of butter and cheese 

 is determined by the action of bacteria on the constituents of milk ; and 



