BACTERIA IN INFECTIOUS DISEASES. 617 



pure, but contained quite a variety of bacteria. In every instance the blood 

 serum was liquefied." As to the morphology he says : "The bacterium va- 

 ries in form according 1 to the various conditions of its nutritive environment 

 and the consequent rate of its development. The most constant and preva- 

 lent form is a short, fine bacillus with rounded or nearly square ends. Those 

 parts of the culture where the nutriment is apparently exhausted show the 

 same "bacilli in short chains, longer bacilli, and bacilli much enlarged at one 

 end or the middle, as if in preparation, for spore formation." As Martin's cul- 

 tures were not pure we have no evidence that his successful inoculations 

 were due to the particular bacillus which attracted his attention. Possibly a 

 microorganism of another class was also present and was carried over from 

 one culture to another. Ruete and Enoch (1893) have also reported success- 

 ful vaccinations in the calf with a micrococcus which they cultivated from 

 vaccine lymph. 



Buttersack (1893) as a result of his researches arrived at the conclusion 

 that there are numerous minute elements in vaccine lymph which do not 

 stain and are sometimes arranged in chains. The subsequent researches of 

 Landmann (1894) and others indicate that the supposed microorganisms of 

 Buttersack are non-living, albuminoid granules, artificially produced by his 

 method of investigation. This view is confirmed by the investigations of 

 Draer (1894). 



Guarnieri (1892), Monti (1894), Piana and Galli-Valerio (1894), and Clarke 

 (1895), have observed amoeboid microorganisms in the pustules of variola and 

 in vaccine lymph which may prove to be the specific infectious agent in this 

 disease. These are described by Guarnieri under the name Cytorycetes 

 variolas and Cytorycetes vacciniae. According to Clarke these amoeboid para- 

 sites belong to the Sprozoa. E. Pfeiffer (1895) has studied this parasite by 

 inoculations into the cornea of rabbits, guinea-pigs, and calves. 



WHOOPING-COUGH. 



No satisfactory demonstration has yet been made of the specific infectious 

 agent in whooping-cough. 



Hitter (1892) has obtained from the nasal and bronchial secretions in cases 

 (eighteen) of whooping-cough a small diplococcus which he believes to be 

 the cause of the disease. This is aerobic, stains by Gram's method, and 

 grows upon nutrient agar in the incubating oven not in bouillon, in gelatin, 

 or 011 potato. 



Cohn and Neumann (1893) in 18 cases in which they made a careful re- 

 search by approved methods were only able to demonstrate the presence of 

 Ritter's diplococcus in one; in two other cases somewhat similar diplococci were 

 found. The bacillus described by Afanassiew in 1887 (No. 119) was also seen 

 occasionally, but was evidently not the specific infectious agent. The micro- 

 organism most constantly found was a streptococcus, apparently identical 

 with Streptococcus pyogenes. This was present in 20 cases out of 25 exam- 

 ined, and in 12 of these it was obtained from bronchial mucus in such num- 

 bers as almost to constitute a pure culture. 



YELLOW FEVER. 



The results of investigations made by the writer in Cuba during the sum- 

 mers of 1888 and 1889 are given in the following summary statement from 

 the Transactions of the Tenth International Medical Congress (Berlin, 1890) : 



Bacterial Researches in Yellow Fever. 



The report relates to investigations made in Havana, Cuba, during the 

 summers of 1888 and 1889, in Decatur, Alabama, during the autumn of 1888, 



43 



