Il8 STUDY AND IDENTIFICATION OF BACTERIA 



In Europe and U. S., Ceratophyttus fasciatus is the common rat flea and it, as well 

 as other species of flea, may transmit the disease. The bedbug will also transmit 

 plague. Fleas suck up the septicaemic blood of infected rats and there is a develop- 

 ment of plague bacilli in the cesophagus with more or less obstruction. When 

 feeding on man or other rats such fleas regurgitate and thus inoculate these plague 

 bacilli. The faeces of such fleas are also infectious. 



In primary pneumonic plague the infective nature is very great and 

 appears to be by the respiratory atrium (from man to man). This 

 was the terrifying type of plague in the black death of the four- 

 teenth century. 



Strong and Teague have shown that of 39 plates exposed before the mouths of 

 patients with pneumonic plague, with marked dyspnoea and pulmonary oedema, but 

 without coughing, only i plate showed plague bacilli. In 39 other experimental 

 plate cultures with coughing on the part of the patients there were 15 plates showing 

 plague bacilli. 



The droplet method of infection is therefore the important one in plague pneu- 

 monia. 



As these droplets are expelled to a considerable distance not only should the 

 respiratory inlets be protected by masks but the conjunctivas with glasses and abra- 

 sions with protective coatings. 



For diagnosis make smears and cultures from material drawn from 

 a bubo by a syringe. (At a later stage, when softening begins, there 

 may not be any bacilli present.) Also, if pneumonic plague, from the 

 sputum. Blood cultures and even blood smears may be employed in 

 septicaemic plague. Formol fuchsin and Archibald's stain make satis- 

 factory stains. Always inoculate a guinea-pig with the material either 

 by rubbing it in with a glass spatula on the shaven skin or by sub- 

 cutaneous injection. 



For prophylaxis the most important method is that of Haffkine. Stalactite bouil- 

 lon cultures of plague are grown for five to six weeks. These are killed by a tem- 

 perature of 65C. for one hour. Lysol (M%) is added to the preparation and from 

 0.5 to 4 c.c. injected, according to the age and size of the individual treated. Sus- 

 ceptibility is reduced about one-fourth, and of those attacked after previous vaccina- 

 tion, the mortality is only about one-fourth of what it is among the noninoculated. 

 Strong prepares a prophylactic vaccine from living plague cultures rendered avirulent. 

 Yersin's serum, made by injecting horses with dead plague cultures and afterward 

 with living ones, is of value prophylactically and has possibly considerable curative 

 power. 



The Eberth, Gartner and Escherich Groups. From a standpoint 

 of cultures in litmus milk and sugar bouillon we can divide the organ- 

 isms related to typhoid at one extreme and the colon at the other into 

 three groups. 



