368 DIPHTHERIA. 



solving, aided by dialysis, a solution is obtained which, on 

 evaporating to dryness, gives a whitish-yellow powder contain- 

 ing the toxic body, though not in a chemically pure condition. 

 From the characters described, Roux and Yersin considered that 

 it belonged to the group of diastases or enzymes. 



The true chemical nature of the diphtheria toxin is still un- 

 known, and the matter is further complicated by the possibility 

 that if a ferment is formed by the bacilli it may produce other 

 toxic bodies of a non-diastatic nature. Guinochet showed that 

 toxin was also formed by the bacilli when grown in urine with 

 no proteid bodies present. After growth had taken place he 

 could not detect proteid bodies in the fluid, but on account of 

 the very minute amount of toxin present, their absence could 

 not be excluded. Uschinsky also found that toxic bodies were 

 produced by diphtheria bacilli when grown in a proteid-free 

 medium. 1 It follows from this that if the true toxin is a proteid, 

 it may be formed by synthesis within the bodies of the bacilli, as 

 well as by a change in the proteids of the culture fluid. Brieger 

 and Boer have separated from diphtheria cultures a toxic body 

 which gives no proteid reaction (vide p. 174). 



Toxic bodies have also been obtained from the tissues of 

 those who have died from diphtheria. Roux and Yersin, by using 

 a filtered watery extract from the spleen from very virulent cases 

 of diphtheria, produced in animals death after wasting and 

 paralysis, and also obtained similar results by employing the 

 urine. The subject of toxic bodies in the tissues has, however, 

 been specially worked out by Sidney Martin. He has separated 

 from the tissues, and especially from the spleen, of patients who 

 have died from diphtheria, by precipitation with alcohol, chemical 

 substances of two kinds, namely, albumoses (proto- and deutero-, 

 but especially the latter), and an organic acid. The albumoses, 

 when injected into rabbits, especially in repeated doses, produce 

 fever, diarrhoea, paresis, and loss of weight, with ultimately a 

 fatal result. As in the experiments with the toxin from cultures, 

 the posterior limbs are first affected ; afterwards the respiratory 

 muscles, and finally the heart, are implicated. He further found 



1 Uschinsky's medium has the following composition: water, 1000 parts; 

 glycerin, 30-40; sodium chloride, 5-7; calcium chloride, .1; magnesium sulphate, 

 .2 .4; di-potassium phosphate, .2 .25; ammonium lactate, 67; sodium asparagi- 

 nate, 3-4. 



