190 



MR. H. A. SMITH ON ANIMAL LIFE 



In this case we find that sulphuric acid has the least 

 harmful effect on that species of animal life, hydrochloric 

 and sulphurous acids following in order. I only lay these 

 results before the Society thinking they may have some 

 interest in themselves. 



I have put my results into a more compact form in the 

 following Tables : — 



Table I. — Acid used, Sulphuric Acid. 



Time allowed 

 to stand. 



Total acidity. 



Remarks. 



days. 



5 



grm. per litre. 

 0*065 



Animal life very abundant. Rotifers 

 in very active condition. 



6 



7 



0*084 

 0*097 



No perceptible difference in the ap- 

 pearance of life. 



Brownish shades now evident in the 

 water ; want of clearness in portion 

 examined: small "clots" of vege- 

 table matter become visible. Roti- 

 fers languid, seemingly disinclined 

 to move. 



8 



0-153 



Life continued for about an hour ; all 

 traces then disappeared. The water 

 presented the appearance of being 

 filled with decomposing and decay- 

 ing organic matter, which was float- 

 ing about in " shreds." 



Table II. — Acid used, Hydrochloric Acid. 



Time allowed 

 to stand. 



Total acidity. 



Remarks. 



days. 



5 



grm. per litre. 

 0*0085 



Same as in Table I. 



6 



0*0109 



No perceptible difference in the appear- 

 ance of solution. 



7 



0*018 



No difference observable. 



8 



0*019 



Life almost immediately extinct. Fluid 

 stil] clear; bodies of Rotifers seen 

 floating in it, but of a dull opal-like 

 colour, and becoming rapidly acted 

 on by the acid, seemingly becoming 

 " shredded." 



