374 



REPORT OF THE COMMISSIONER OF FISHERIES. 



Table IV. — Shoioing nitrogen and oxygen content {in cubic centimeters per liter, reduced 

 to 0° C. and 760 mm., dnj) of various {fresh) iraters at and near fisheries station, 

 Nashua, N. 11. 



Source of sample. 



Hatchery well No. 1 



Same, second determination 



Same, deaerated drop by drop 



Hatchery well No. 5 



Hatchery well No. 11 



AVell in rearing pond No. 3 



Well in rearing pond No. IC 



Reservoir pond water 



Same, through deaerating box 



Creek water, total station flow, aer- 

 ated and deaerated by natural 

 flow 



Largest I'ennichuck well, source of 

 Nashua city sujiply 



Smaller Pennichnck well 



Pennichuck water from service tap 

 at hatchery 



Colerain Brook, a well-aerated nat- 

 ural stream 



Kain water freshly caught 



Date. 



1901. 

 Apr. 2G 

 Apr. 28 

 Apr. 29 

 May 3 

 Apr. 30 

 Apr. 27 

 Apr. 28 

 Apr. 27 

 ....do... 



Apr. 30 



Mav 2 

 ...do... 



Apr. 29 



Apr. 30 

 Apr. 29 



a-*-' 



8.0 



8.0 



9.5 



8.0 



8.0 • 



8.0 



8.0 



8.75 



8.75 



8.5 



11. 5 

 11.5 



12.0 

 11.0 



Actual content 

 c.c. per liter. 



Nitro- 

 gen. 



17.5 

 18.1 

 15.0 

 17.8 

 18. C 

 17.5 

 17.9 

 17.2 

 16.4 



17.6 

 18.3 



14.5 

 14.8 



Oxy- 

 gen. 



3.3 

 3.4 

 7.4 

 2.9 

 1.6 

 3.1 

 3.8 

 5.0 

 6.7 



0. 8 



2.1 

 2.2 



7.0 

 6.0 



Normal content 

 when saturated 



with air at 

 given tempera- 

 ture, and pre- 

 vailing pressure 

 c. 0. per liter. 



Petters-! 



son and Wink- 



Son- 

 dC-n. 



N. 



16.00 

 16.00 

 15. 35 

 16.14 

 15.72 

 16.00 

 16.00 

 1.5. 77 

 15. 73 



14.94 

 14.91 



16.24 



14. 45 

 14. 87 



ler. 



8.26 

 8.26 

 7.89 

 8.33 

 8.11 

 8.26 

 8.26 

 8.13 

 8.11 



7.65 



7.65 



Excess -I- or 



deficit — c. c. 



per liter. 



-1-1.5 

 -f2.2 

 -0. 35 

 -j-1. 66 

 +2. 88 

 -1-1.6 

 H-2.0 

 -fl.43 

 "1-0.67 



-f 0. 39 



-i-2.66 

 +3.36 



-0.84 



-0.05 

 -0.07 



-4.96 

 -4.86 

 -0.49 

 -5. 43 

 -6. 51 

 -5.16 

 -4.46 

 -3.13 

 -1.41 



-1.26 



-6.55 

 -6.45 



-0.39 

 -1.01 



Notes. — Presumably normal waters show, according to Tables III and IV, slight nominal excesses 

 or deficiencies of nitrogen, and always a deficiency of oxygen. These discrepancies represent limils 

 of accuracy of apparatus and methods as used iu the field, and the personal equation. Moreover, 

 saturation data vary witliin rather wide limits. 



The figures for the dissolved COo are not included in the tables, as having no particular relation to 

 the present subject. They are considerably higher for fresh water containing a nitrogen excess than 

 for normal water, the former averaging 5.3 c. c. per liter with extremes of 3.6 and 7.4, the latter 1.8 

 with extremes of 1.6 and 2.1. These figures include the semibound carbonate. 



SUMMARY. 



1. Fishes and some other organisiiis show gas .symptoms of consid- 

 erable variety' and of a pathologic nature. Man}^ of these are due to 

 one cause and may be grouped together as a pathologic unity, the gas 

 disease. An exophthalmia, or pop-eye, is one of the chief lesions. 



2. Bacteria are not in any wa}'^ concerned in the gas disease here 

 considered, but may cause similar lesions. 



3. The immediate cause of death in the gas disease is usually 

 asph3o:iation from gas embolism in the gill lilaments, or heart, or both. 



•4. This embolic gas is due to an excess of dissolycd ai-r in the blood, 

 which may be immediatel}^ caused by a rapid reduction of pressure, or 

 by an excess of dissolycd gas in the water, or b}^ a combination of 

 both. 



