397 



In man ammonia causes comatose conditions or delirium and dys- 

 pnoea, death coming very suddenly (Witthaus and Becker). In 

 frogs and mammals it causes increased reflex irritability which may be 

 followed by tetanic convulsions (Cushny). When first placed in am- 

 monia solution which will produce death in an hour or less, fishes are 

 often much stimulated, the head often floating low^er than the rest of 

 the body. Erratic movements follow after a time and the fish usually 

 turns over in convulsion and remains comparatively still with peculiar 

 twitchings of the tail and fins until death. Ammonia is less toxic in 

 distilled water than in water with carbonates. Five parts per million 

 is fatal to fishes. Weigelt found that o.i% solution killed tench in 45 

 minutes. 



Fishes do not ordinarily turn back when they encounter ammonia, 

 but swim into it without giving any of the avoiding reactions which 

 characterize the movements of fishes with reference to such environ- 

 mental substances as carbon dioxide. The reaction is usually indefinite 

 or indifferent (Shelford and Allee, Wells). Pimeplialcs was positive 

 to it in alkaline water; Lcponiis Jiiiuiilis, Notropis and Ahrauiis 

 crysolcuca were positive to fatal concentrations in acid and in alkaline 

 water (4-6 cc. per 1. of COo). Wells found that in very strong con- 

 centrations the fish selected a point in the gradient tank near the centre 

 and avoided both ends but the concentration of ammonia in the part 

 of the tank selected was such as to cause the death of the fishes in a 

 short time (Chart II, graphs 14 and 15 ; Chart V, graph 55). 



Animoniiini carbonate. 



It is present in quantity in liquors from all parts of the manufactur- 

 ing plant, most abundantly from the last condenser and washers. A 

 solution of 20 gm. per liter was prepared and its actual strength deter- 

 mined by titrating with standard hydrochloric acid and methyl orange 

 indicator. Its general effects are similar to ammonia. Erratic move- 

 ment occurs oftener than in the case of ammonia. Fishes are usually 

 positive to strong concentrations, e. g., i gm. per liter, but they do not 

 act with precision as in the case of other alkalies (Chart II, graph 16). 



Ammonium chloride. 



It is abundant in the liquor from all parts of an ordinary plant 

 (Lunge 3d ed., 741). 



A solution was made by dissolving 8 gm. per liter of water. The 

 solution was tested by adding a definite cjuantity of NaOH to a known 

 amount of the solution and iDoiling until the vapor did not turn litmus 

 blue. The remaining free alkali was titrated with standard acid and 



