TETANUS 4f 



clinical characters. It is safest to regard any patient who presents 

 these bacilli as being infectious. In other words, in the presen 

 state of our knowledge it is best not to draw any distinctioi 

 between Hoffmann's bacillus and the true diphtheria bacillus, as 

 far as infectivity is concerned.* 



A negative result may mean — 



{a) That the patient is not suffering from diphtheria. 



(b) That the swab did not touch the affected area. 



We exclude errors in technique and observation. 



A sterile culture may mean — 



{a) That an antiseptic was used too soon before taking the swab. 



(b) That the diseased portion of the throat was not touched. 

 Other parts of the mouth contain numerous bacteria, but many ol 

 them do not grow well on blood-serum or ascitic agar. 



We again exclude errors arising in the laboratory. 



Whenever the culture-tube remains sterile, the examination 

 should be repeated, 



TETANUS 



The pathology of tetanus is very much like that of diphtheria. 

 In each disease the specific bacilli are localized at or near the 

 region at which they enter the body, and form a toxin which 

 affects distant organs. In the case of diphtheria, as we have seen, 

 the toxin passes by the blood-stream, but in tetanus it creeps from 

 the region where it is produced up the peripheral nerves to the 

 brain and spinal cord. In each case research has shown that an 

 antitoxin is formed which neutralizes this toxin and prevents it 

 from uniting with the cells of the body, but which has not the 

 power of turning it out from such a combination. In other words, 

 tetanus antitoxin, like that of diphtheria, is preventive, but not 

 curative. But here, unfortunately, the resemblance between the 

 two diseases ceases. The local lesion in diphtheria is obvious, 

 and its presence causes a good deal of inconvenience to the patient ; 



* Since the publication of the first edition of this book there has been much 

 controversy on this point, but I have seen nothing which leads me to alter the 

 above opinion, though it is certainly true that laboratory evidence of the 

 relation of the organisms appears lacking. It may be noted that those who 

 deny the relation of Hoffmann's bacillus to diphtheria do so, for the most part, 

 on this failure of laboratory evidence, whilst those who look on Hoffmann's 

 bacillus with suspicion do so mainly on clinical grounds. (For an account of 

 other forms of sore throat, see p. 105.) 



