36 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 
understood, adapt it to the uses to which menhaden oil successfully 
has been applied, conspicuous among which is its utilization as a 
lubricant, and especially in the paint and enamel industries. 1 
GLUE. 
Fish glue made from salmon is regarded as low grade and of 
proportionately slight value. In this particular it differs markedly 
from that prepared from cod skins. It is used with success in the 
preparation of sizings and allied materials. 
METHODS PROPOSED FOR THE TREATMENT OF SALMON CANNERY 
WASTE ON A LARGE SCALE. 
In the treatment of salmon cannery waste two methods immedi- 
ately suggest themselves: (1) Treatment in large units, and (2) in 
small units. The former at first glance appears the more desirable, 
as it generally is understood that large-scale manufacturing opera- 
tions are more economical in both labor and equipment than those 
conducted on a small scale. And it is the large-unit plan that now is 
in oj)eration; without exception, all the salmon scrap at present 
produced is the product of the large-unit plants. The foregoing de- 
scription, then, of the present method employed in rendering salmon 
waste applies in a large measure to that of a proposed central ren- 
dering plant. In fact, it may be argued that it is not wise to diverge 
from the methods now in vogue as they are the only ones which 
haA^e been applied with any commercial success whatever. 
THE CENTRAL RENDERING STATION. 
The failures in the operation of centrally located rendering plants 
have been as numerous as and far more conspicuous than the suc- 
cesses. The causes operating to bring about these failures, it appears 
at this distance, were manj^fold. Speaking of the failures collec- 
tively and not as individuals, it is evident that over capitalization 
and extravagance in expenditure for equipment, the failure of equip- 
ment to yield its expected performance, errors in the location of the 
plant, and general inexperience all contributed. 
The plan has inherent faults. These are twofold: The high ex- 
pense involved in hauling the raw material to the plant and the lack 
of machinery which would make the rendering process continuous, 
automatic, and economical. A further disadvantage, applying to 
both proposed methods but in greater degree perhaps to that of the 
central plant, is the shortness of the season during which the plant 
would be in operation. In this discussion the adoption of the plan 
is opposed further on the ground a of its general failure to meet the 
demands of the problem. 
1 For a brief discussion of menhaden oil see ibid., p. 46 et seq. 
