534 FOOD PRESERVATION 
mation occurred only on certain food substances, as meat, but Dickson 
has shown that it may take place in such foods as canned beans and 
peas. 
The symptoms have beeh stated by Dickson (1915). 
The symptomology of botulism has been summarized by Van Ermengen as a 
neuroparalytic symptom complex with disturbances of secretion and symmet- 
rical partial or complete motor paralyses which apparently have their seat in 
lesions of the central nervous system. The first symptoms do not occur earlier 
than from twelve to twenty-four hours after ingestion of the infected food, 
although they may appear much later. In contrast to the usual types of food 
poisoning there is apt to be little evidence of gastro-intestinal disturbance, and 
obstinate constipation is more frequent than is diarrhoea. There is usually 
a, decrease, but there may be an increase in the secretion of saliva and of mucus 
in the mouth and in the throat, when mucus is present it 1s extremely viscid. 
There is early disturbance of the external and internal muscles of the eyes which 
manifests itself by blepharoptosis mydriasis, disturbances of accommodation, 
diplopia and strabismus. General muscular weakness is common. There 
may be dysphasia or aphonia and there is usually great difficulty in swallowing. 
The absence of sensory disturbances is characteristic. 
The symptoms gradually increase in severity and when death occurs it is 
usually from respiratory or cardiac failure, as in bulbar paralysis. When 
recovery takes place the.e is usually a long and tedious convalescence with a 
slow return of muscular strength. The condition so closely resembles that 
seen in gelsemium or hyoscyamin poisoning, polyomyelitis, cerebral gyphilis 
and bulbar paralysis that isolated cases may readily escape recognition, but 
when a series of cases is seen and especially if all have partaken of a common 
article of food there is usually little difficulty in establishing a diagnosis. 
Botulism may be diagnosed microscopically by detecting the Bacil- 
lus botulinus in the suspected food. The bouillon cultures should be 
tested for toxin and inoculated food fed to laboratory animals. In 
the cultural examination of the food, careful anaerobic technique should 
be used. 
Bacillus botulinus has caused severe poisonings in modern times. 
Wilbur and Ophiils (1914) reported the investigation of an epidemic 
which was caused by home-canned string beans. Dickson (1915) has 
mentioned some other epidemics. He (1917) called attention also to 
the fact that vegetables put up by the cold-pack method might cause 
the disease. This was.later denied, to a certain extent, by the U. 8. 
Department of Agriculture. Fischer (1906) studied an epidemic of 
botulism resulting from the eating of bean salad. The symptoms were 
characteristic and appeared between twenty-four and forty-eight hours. 
The beans were canned and when opened were not cooked since they 
