April 9, 1897.] 



SCIENCE. 



563 



water, and water from marshy countries. 

 For more than half a century before this 

 time a number of investigators had proved 

 the dangerous character of old sausage 

 meats, bread and the like. Kerner con- 

 cluded that they contained a fatty acid to 

 which the poisonous action was due; others 

 confirmed these ideas and came to similar 

 conclusions in regard to poisonous cheese. 

 In 1856 Panum asserted, as a result of his 

 studies upon the poisons found in putrid 

 animal matter, that these poisons might be 

 formed by some active plant cell, but their 

 injurious effect was independent of these 

 cells. He demonstrated that fixed non- vol- 

 atile poisons could be extracted from putrid 

 matter which were soluble in water and 

 alcohol, not destroyed by heat, and pro- 

 duced the same effects after they had been 

 submitted to a high temperature as before. 

 These poisons he found to be intense in 

 their action, 0.012 grams sufficing to cause 

 the death of a small animal. In 1866 

 Bence-Jones obtained from the liver a sub- 

 stance which, with dilute sulphuric acid, 

 gave a bright blue fluorescence like that 

 noted in similar solutions of quinine. Prob- 

 ably this was the product of what we now 

 call fluorescing bacteria. 



The work of Pasteur threw light upon 

 the origins of these poisons. As the ferment 

 causes the alteration in the grape juice, so 

 do microscopic forms of life bring about the 

 changes which take place in dead animal and 

 vegetable matter, and also those conditions 

 in the living body which we call disease. 



Many of these microscopic forms of single- 

 celled plants, the bacteria, have their natural 

 habitat upon dead organic matter, but they 

 may flourish in the living body and are 

 almost unlimited in variety, appearance and 

 behavior. It is possible also to cultivate 

 them upon specially prepared solutions after 

 their individual peculiarities have been 

 studied. Some thrive best in light, others 

 in darkness ; some like a goodly supply of 



oxygen, others prefer nitrogen ; some are 

 very sensitive to changes of temperature, 

 while others readily accustom themselves 

 to vicissitudes. 



These different bacteria further are some- 

 what eccentric within as well as without 

 the animal body. Some, as the diphtheria 

 germs, find their most comfortable habitat 

 upon certain mucous membranes, others in 

 the lungs, some in the digestive tract, still 

 others in the blood, while others again con- 

 fine themselves to certain external cells and 

 membranes. In their artificial cultivation 

 this eccentricity is equally apparent. While 

 nearly all thrive upon a beef broth, some 

 prefer the beef broth with an excess of acid, 

 others with an excess of alkali. Some de- 

 mand the addition of sugar or glycerine, 

 others the addition of sugar together with 

 acid, while some are satisfied with a diet 

 of phosphates, salt and water. These pecu- 

 liarities have to be studied for each germ, 

 and while many can accommodate them- 

 selves to their surroundings, and while the 

 same germ grown upon different media pro- 

 duces the same substances, the amount of each 

 substance is a varying one, and in cultiva- 

 ting them artificially we must find which 

 diet gives rise to the largest amount of the 

 most active products. 



Shortly after the work of Panum just re- 

 ferred to, the Italian chemist Selmi out- 

 lined methods of extracting poisonous prin- 

 ciples from dead animal matter, and gave 

 to these substances the name ptomaines, on 

 account of their origin. Later, in 1876, the 

 first analysis of a ptomaine was made by 

 Nencki and its formula determined. Fur- 

 ther experiments showed that volatile and 

 non-volatile substances, alkaline in charac- 

 ter, could be obtained from various portions 

 of the animal body, often from fresh mate- 

 rial and also from the cultures of bacteria. 

 These ptomaines were found to resemble 

 the alkaloids in their chemical reactions. 



In 1882-83 Brieger succeeded in separa- 



