ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 103 



Salter. The weakest, known as Hoffmann's or the pseudo-diphtheria 

 bacillus, and representing the most attenuated form of the Klebs- 

 Loeffler bacillus, is capable of killing only certain highly susceptible 

 small birds of the finch tribe. Organisms of a slightly higher degree 

 of virulence can kill other and more resistant small birds of the bunting 

 family. Others still more active can cause larger birds (Merulidse) to 

 succumb; whilst the most virulent of all can kill certain rodents, e.g. 

 guinea-pigs. 



Physiological analysis of the pseudo-diphtheria toxin shows that it 

 contains bodies identical with or allied to certain of the constituents of 

 the true diphtheria poison known as toxoids, and these bodies possess 

 th« power of neutralising or " fixing " antitoxic serum, and to a degree 

 much greater than that of the true toxin. To this product Ehrlich gave 

 the name of protoxid. The presence of this common product of the 

 diphtheria and the pseudo-diphtheria bacilli is another argument in 

 favour of the identity of the two organisms. 



Bacillus of Acute Rheumatism.* — Prof. Savtschenko found the 

 microbe first isolated by Achalme in five out of six cases of rheumatism. 

 The rodlet is of variable height ; it forms terminal spores ; it is easily 

 stained with anilin dyes and also by Gram's method. It is an essential 

 aerobe. Its optimum temperature is from 30°-37°. The most favour- 

 able medium is bouillon with 0*5 per cent, lactose and 0*33 sterilised 

 milk. The microbe is extremely pathogenic to laboratory animals, but 

 they may be immunised by successive inoculations. It is extremely 

 sensitive to salicylate of soda. In the bouillon-lactose-milk medium the 

 lactic fermentation is excited, the milk being at the same time coagu- 

 lated. The microbe grows equally well in extract of muscle. Its 

 virulence is weakened by repeated cultivation, but may be restored by 

 passage through animals. From ■ 5—1 ccm. of human blood is required 

 for each tube, as the microbe is infrequent. 



Constitution of the Diphtheritic Poison. \ — M. Th. Madsen discus- 

 ses at some length the composition of the diphtheritic poison, and after 

 describing the views of Ehrlich on the subject, gives an account of his 

 own experiments with four different samples. The net result appears 

 to be that the diphtheria bacillus produces two different substances 

 in bouillon cultures, toxins and toxones, both of which fix antitoxin. 

 The toxins are divisible into three groups which differ in their degree of 

 affinity for antitoxin. Each of these three groups has two modifications 

 which differ from each other in their degree of stability. Modification a is 

 easily converted into toxoid, by which is meant toxin that has lost its 

 power of killing an animal, though it has retained the property of 

 fixing antitoxins. In each equivalent of the diphtheritic poison are two 

 independent atomic groups : — (1) the haptophore group, which possesses 

 fixative properties only ; (2) the toxophore group, which possesses toxic 

 properties and produces the specific effects of the poison through the 

 intermediary of the fixative haptophore group. The toxones possess 

 analogous, though feebler, properties, and undergo the same changes as 

 the toxins. The toxones are secreted by the microbes at the same time 



* Archiv. Eusses Pathol. Med. et Back, v. (1898) p.',558. See Physiologiste Russe, 

 i. (1899) pp. 223-4. f Ann. Inst. Pasteur, xiii. (1899) pp. 568-80, 801-32. 



