Licence: Public Domain Mark
Credit: Acute rheumatism in children in its relation to heart disease. Source: Wellcome Collection.
24/114 (page 12)
Licence: Public Domain Mark
Credit: Acute rheumatism in children in its relation to heart disease. Source: Wellcome Collection.
![‘as being equally competent observers. These require some discussion, though I may say at the outset that I am not prepared ‘to offer any categorical explanation. In the first place, many of the workers who have obtained a ‘substantial proportion of positives stress the importance of technique. Clawson’s proportion seems to have been remarkably high ; so I will now quote another investigation. In an article on the detection of streptococci in the blood, Freund and Berger? (1924) insisted on the use of liquid media. They placed the clot from 5-10 c.c. of blood in an Erlenmeyer flask containing 50 c.c. of a 10 per cent. horse serum broth. The cultures were incubated usually for 4 to 6 days, a longer period not being often required. Every 24 hours, a few drops were transferred to a blood agar plate. By this means they were able to demonstrate streptococci, in the majority of cases, in 1-2 days. Out of 23 cases of poly- arthritis rheumatica they found viridans in 14 (7 of which showed clinical signs of heart lesions) ; in one they obtained both viridans and. haemolyticus ; the remaining 8 were negative. These results may be compared with their observations on cases of endocar- ditis :—Endocarditis lenta (19 cases) ; viridans in 16, both viridans and haemolyticus in 3. Acute endocarditis (18 cases) ; viridans in 14, haemolyticus in 3, one negative (one test only). It may be mentioned that, in polyarthritis rheumatica, the authors regarded the streptococci as secondary invaders. Investigations in which the findings were mainly or entirely negative require careful handling. Full details of technique are not always given. ‘This is rather unfortunate because one would like to fee] assured that the authors’ methods were quite as good as those employed by bacteriologists who were more successful. But I am not disposed to emphasise this point. One dislikes the vexatious and somewhat gratuitous style of criticism which suggests that a cifferent technique would have converted some of the negatives into positives. When there is no definite evidence in support of a contrary opinion, it is preferable to assume that a negative result indicated the absence of viridans in the material examined. As an interesting example of negative results I quote from a recent article by C. P. Miller®> (1924), who investigated 16 cases of rheumatic fever and attempted to transmit the disease to rabbits and guinea-pigs by injecting blood and other material obtained. from his patients. Such material was obtained “ either before the patients had received antirheumatic medication, or after a sufficient time following the discontinuance of the treatment for its effect to have disappeared.” He also stated that “ the blood was withdrawn by venipuncture during the acute febrile state while the polyarthritis was still developing.” I am mainly concerned here with the protocol in which he records his examina- tions of the patients’ blood. Cultures from the blood (on a number of occasions varying from 1 to 7) were made from 14 of his cases. Thirteen of these cases, involving 51 cultures, were consistently](https://iiif.wellcomecollection.org/image/b32183690_0024.jp2/full/800%2C/0/default.jpg)
