St REPORT OF THE COMMISSIONER OF FISHERIES. 
TaBiE IV.—Showing nitrogen and oxygen content (in cubic centimeters per liter, reduced 
to 0° C. and 760 mm., dry) of various (fresh) waters at and near jisheries siation, 
Nashua, N. H. 
ca Normal content 
2 when puutaled 
- 4 with air at Excess + or 
s een eae given tempera-| deficit — c. c. 
a ore * | ture, and pre- per liter. 
Eo vailing pressure 
Source of sample. Date. oe | c.g tes PaaS 
(>) | 
Beet |Petters- 
= son and oe } 
i Nitro- | Oxy- | Son- | ler. E 
= gen. gen. dén. 1 ea) 0: 
a N, oO. | | 
1904 
Hatchery wiellwNo. Li oeccces ses eee ee Apr. 26 | 8.0 17.5 3.3 | 16.00 8.26 | +1.5 —4, 96 
Same, second determination........ Apr. 28 | 8.0 18.1 3.4] 16.00 8.26 | +2.2 —4. 86 
Same, deaerated drop by drop...... Apr. 29 | 9.5 15.0 4.4), J5585 7.89 | —0.35 0. 49 
Hatchery awelluNonpeeens. oases ones May 3] 8.0 17.8 2.9 | 16.14 8.33 | +1. 66 —). 43 
FBT Chery uWwiellIN Os lleesee mene ne eae | Apr. 30 | 8.0 18.6 LAG} Lo are 8.11 | +2.88 6. 51 
Wellin rearing pond No. 3......... Apr. 27 | 8.0 17.5 3.1] 16.00 8.26 | +1.6 —5, 16 
Wellin rearing pond No. 16........ Apr. 28 | 8.0 17.9 3.8] 16.00 8.26 | +2.0 —4, 46 
Reservoir pond water........®...-. Apr. 27 | 8.75 Wee. 5.0] 15.77 8.13 | +1.43} —3.13 
Same, through deaerating box ..... Sogo Saaibyshy 75) 16.4 Caf 5.73 8.11 | +0. 67 —1,4 
Creek water, total station flow, aer- 
ated and deaerated by natural 
fl OWeeeesss = Scene mee rene Scieetie Apr. 380 | 8.5 16.0 6.8} 15.61 8.05 | +0.39 ) 1.25 
Largest Pennichuck well, source of | 
Nashua city: supply ss-ss-.-+-22-05 May 2 11.5 EG: | Posil 14. 94 7.65 | +2. 66 | —5, 55 
Smaller Pennichuck well........... paadOmoe Mal ob 18.3 2.2} 14.94 7.65 | +3.36 | «—5d 
Pennichuck water from service tap 
aiinaichenyass seep eee eee eee Apr. 29 | 7.0 15.4 6.6] 16.24 8.40 | —0.84| —1.80 
Colerain Brook, a well-aerated nat- 
Ural sires ose eee ee ee Apr. 380 {12.0 14.5 WaOOT 445 7.39 | —0.05 —0.39 
Rain water freshly caught.........- Apr. 29 /11.0 14.8 6.6} 14.87 7.61 | —0.07 | —1.01 
Nores.—Presumably normal waters show, according to Tables III and LY, slight nominal excesses 
or deficiencies of nitrogen, and always a deficiency of oxygen. These discrepancies represent limits 
of accuracy of apparatus and methods as used in the field, and the personal equation. Moreover, 
saturation data vary within rather wide limits. 
The figures for the dissolved CO, 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. 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 organisms show gas symptoms of consid- 
erable variety and of a pathologic nature. Many 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 way concerned in the gas disease here 
considered, but may cause similar lesions. 
3. The immediate cause of death in the gas disease is usually 
asphyxiation from gas embolism in the gill filaments, or heart, or both. 
4. This embolic gas is due to an excess of dissolved air in the blood, 
which may be immediately caused by a rapid reduction of pressure, or 
by an excess of dissolved gas in the water, or by a combination of 
both. 
