410 CONSIDERATION OF CARBON COMPOUNDS 



Other poisonous proteids have been obtained from cultures of the tetanus 

 bacillus, of the comma bacillus (found in cholera patients), of the Eberth 

 bacillus (found in typhoid-fever patients), and from micro-organisms found in 

 the intestines and stools of children suffering from summer diarrhoea. The 

 proteids in the latter case are highly poisonous, causing, when injected under 

 the skin of dogs, vomiting, purging, collapse, and death. 



Antitoxins. After an infectious disease has passed over, there are 

 present in the system, as a result of the action of the micro-organisms 

 upon the tissues of the body, certain substances which have the 

 power of protecting the individual to a certain extent against other 

 attacks of the same disease. These bodies are known as antitoxins ; 

 their chemical composition is yet unknown. By some they are con- 

 sidered albumins, by others globulins ; still others claim them to be 

 nucleins. 



The antitoxins are found in the blood-serum of the animals which have 

 recovered from an infectious disease, and this serum may be utilized in the 

 treatment of the same disease in other individuals, and in even rendering 

 immune others susceptible to that disease. (Blood-serum therapy of Behring.) 



Practically, animals such as cows, horses, dogs, goats, are rendered highly 

 immune to such diseases as tetanus and diphtheria by injecting them with 

 attenuated cultures of the micro-organisms (causing these diseases) or their 

 toxins, and then with gradually increasing doses of virulent cultures until the 

 animals become highly refractory to these diseases. The blood-serum of such 

 animals is now extensively used with remarkable success in the treatment of 

 tetanus and diphtheria. 



51. PEOTEIDS (ALBUMINOUS SUBSTANCES). 



Occurrence in nature. Proteids form the chief part of the solid 

 and liquid constituents of the animal body ; they occur in blood, 



QUESTIONS. 491. State the general physical and chemical properties of 

 alkaloids. 492. Give a general method for the extraction and separation of 

 alkaloids from vegetables. 493. Mention the chief constituents of opium, and 

 explain the process for determining the percentage of morphine in opium. 



494. Mention the properties of morphine and its salts ; give tests for them. 



495. Mention the principal alkaloids found in cinchona bark, and give a pro- 

 cess by which the total quantity of these alkaloids and of quinine may be 

 determined. 496. State the physical and chemical properties of quinine and 

 cinchonine. Which of their salts are official, and by what tests may these 

 alkaloids be recognized and distinguished from each other? 497. Give tests for 

 strychnine, brucine, atropine, and veratrine. 498. What is the chemical rela- 

 tionship between xanthine, caffeine and theobromine ? 499. Mention proper- 

 ties of and give tests for cocaine. 500. Mention the characteristic physical, 

 chemical, and physiological properties of ptomaines. 



