434 Dr. G. Sims Woodhead [Feb. 8, 



part been redeemed, to diminish the diphtheria case mortality in a 

 very remarkable manner. 



Diphtheria is primarily an inflammation of the mucous membrane 

 (the moist skin) of the tonsils, of the soft palate, of the upper part of 

 the gullet, and of the upper part of the windpipe. [Illustration shown.] 

 During the course of this inflammation, which appears to be set up 

 by the action of a special bacillus, there are usually thrown out some 

 of the fluid elements of the blood and some of the white cells that 

 float in the blood ; these form a soft toughish layer or film which 

 offers an excellent food and resting place for this bacillus of diph- 

 theria, which under such favourable conditions secretes or manu- 

 factures a most virulent poison. This poison is rapidly absorbed 

 into the blood and is carried to various parts of the body ; its effects 

 are evident at first only on the nervous system, but afterwards on the 

 muscles. 



First as to the bacillus. In 1875 Klebs described a short bacillus 

 which he found on the surface of the greyish leather-like diphtheritic 

 false membrane or film. [Illustration shown.] Following up these 

 observations, Loeffler traced a definite etiological relationship between 

 this bacillus and diphtheria. First he obtained pure cultures of the 

 bacillus by growing it on solidified blood serum, or on a mixture of 

 three parts of blood serum and one part of neutralised beef bouillon 

 containing extract of beef, 1 per cent, of peptone, 0*5 per cent, of 

 common salt, and 1 per cent, of grape sugar. This organism may be 

 readily detached from the surface of the false membrane by pressing 

 firmly but gently with a little bit of cotton wadding twisted round 

 the end of an iron wire or an ordinary penholder. [Illustration shown.] 

 When stained and examined under the microscope, the diphtheria 

 bacilli are found to be small rods from 3 to 6 /x (1 /x, = 25 ^ 00 of 

 an inch) in length, fairly plump, straight, or slightly curved, some- 

 times wedge-shaped or pointed [Illustration shown], but usually 

 somewhat enlarged and rounded at the ends, where also in stained 

 specimens, the protoplasm is more deeply tinted than in the centre. 

 This organism grows singly or in groups, or felted together to form 

 a net-work ; it may occur in irregular masses of considerable size. 

 When these bacilli have been growing for some time on an artificial 

 nutrient medium, they appear to be segmented, the stained material 

 accumulating in small round nodules placed at intervals within a 

 kind of membrane which is only very delicately tinted. During the 

 past five weeks I have examined about 500 specimens taken from the 

 throats of diphtheria patients, and I may say that in nearly every 

 case where the disease has been diagnosed by the physician in charge, 

 as being one of diphtheria, these typical bacilli have been found, 

 whilst in those cases in which there was any doubt as to the nature 

 of the disease, similar bacilli were found in some, but not in others. 



This is of importance, because we shall find that this bacillus 

 gives us the substance with which animals are rendered immune to 

 the attacks of the bacillus itself, these immune animals in turn sup- 



