48 POPULAR SCIENCE MONTHLY. 



chcniical poisons either before or after the food has been eaten. 

 This is the most common form of food poisoning known in this 

 country. 



We will briefly discuss some foods most likely to prove harm- 

 ful to man. 



Mussel Poisoning. — It has long been known that this bivalve 

 is occasionally poisonous. Three forms of mussel poisoning are 

 recognized. The first, known as Mytilotoxismus gastricus, is ac- 

 companied by symptoms practically identical with those of cholera 

 morbus. At first there is nausea, followed by vomiting, which may 

 continue for hours. In severe cases the walls of the stomach are so 

 seriously altered that the vomited matter contains considerable 

 quantities of blood. Vomiting is usually accompanied by severe 

 and painful purging. The heart may be markedly affected, and 

 death may result from failure of this organ. Examination after 

 death from this cause shows the stomach and small intestines to be 

 highly inflamed. 



The second form of mussel poisoning is knoAvn as Mytilotoxis- 

 rtius exanthematicus on account of visible changes in the skin. At 

 first there is a sensation of heat, usually beginning in the eyelids, 

 then spreading to the face, and finally extending over the whole 

 body. This sensation is followed by an eruption, which is accom- 

 panied by intolerable itching. In severe cases the breathing be- 

 comes labored, the face grows livid, consciousness is lost, and death 

 may result within two or three days. 



The most frequently observed form of mussel poisoning is 

 that designated as Mytilotoxismus paralyticus. As early as 1827 

 Combe reported his observations upon thirty persons who had suf- 

 fered from this kind of mussel poisoning. The first symptoms, as 

 a rule, appeared within two hours after eating the poisonous food. 

 Some suffered from nausea and vomiting, but those were not con- 

 stant or lasting symptoms. All complained of a prickly feeling 

 in the hands, heat and constriction of the throat, difficulty of swal- 

 lowing and speaking, numbness about the mouth, gradually extend- 

 ing over the face and to the arms, with great debility of the limbs. 

 Most of the sufferers were unable to stand; the action of the heart 

 was feeble, and the face grew pale and expressed much anxiety. 

 Two of the thirty cases terminated fatally. Post-mortem examina- 

 tion showed no abnormality. 



Many opinions have been expressed concerning the nature of 

 harmful mussels. Until quite recently it was a common belief that 

 certain species are constantly toxic. Virchow has attempted to 

 describe the dangerous variety of mussels, stating that it has a 

 brighter shell, sweeter, more penetrating, bouillonlike odor than 



