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[Vol. XVII. No. 436 



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THE ACTUAL NUMBER OF TUBERCLE BACILLI 

 WHICH MAY BE PRESENT IN TUBERCULOUS 

 SPUTUM. 



Dr. George H. F. Nuttall of Johns Hopkins Univer- 

 sity, in the last number of the "Johns Hopkins Hospital 

 Bulletin,'" describes at length a method by which he has 

 been able to make accurate estimates of the actual numbers 

 of tubercle bacilli present in tuberculous sputum. His com- 

 munication is accompanied by cuts of the apparatus used. 

 The methods heretofore employed for estimatintr simply the 

 relative number of tubercle bacilli in sputum are condemned 

 as unscientific. NuttalVs observations for the first time give 

 us an idea of the enormous number of tubercle bacilli which 

 a patient may expectorate in the course of twenty-four 

 hours. 



In three cases undergoing the Koch treatment observations 

 on the numbers of bacilli in the sputum were made every 

 f»w days. In the first case the patient expectorated two 

 billions of tubercle bacilli during the twenty-four hours; 

 after the patient was inoculated with tuberculine the num- 

 ber of bacilli rose to three and four billions; after the inocu- 

 lations ceased the number fell again to two billions. 



In the second case the number of bacilli in the sputum 

 varied between twenty and one hundred and sixty-five mil- 

 lions on the days preceding the Koch inoculations, rose 

 irregularly to two hundred and eighty- three millions after 

 the first inoculation, and fell to onlj' two liundred and sixty- 

 five thousand by the time the sixteenth inoculation had been 

 reached. The third case showed a decrease from seventy 

 millions before the inoculations to twelve and nineteen mil- 

 lions after treatment had commenced. 



A great rise in the number of tubercle bacilli in sputum 

 was observed in one case (which was not undergoing the 

 Koch treatment) to occur simultaneously with the appear- 

 ance of elastic tissue. The number of bacilli in this case rose 

 from between three and four hundred millions to over four 

 billions. 



• A Method for the Estimation of the Actual Number of Tubercle Bacilli iu 

 Tuberculous Sputum. With a Note on the General Application cf the Method 

 to Bacteriology. By George H. F. Nuttall, M.D., Ph.D. (Gottingen). Reported 

 Setpre the jlobns Hopkins Hospital Medical Society, April 6, 1891. 



The accuracy of the method is shown by a number of con- 

 trol and culture experiments. Nuttall believes his method 

 will prove valuable in any experiments where it is desirable 

 to introduce a definite number of organisms into culture 

 media, disinfectants, etc. In point of accuracy it far sur- 

 passes the loop method generally employed. With such 

 organisms as the tubercle bacillus this method will enable 

 the experimenter to determine the number he is inoculating 

 into an animal in a way that has not been possible hitherto. 

 Inoculations made under such conditions will clearly show 

 the difference in degree of virulence possessed by various 

 organisms, as also the relation between the number of bac- 

 teria introduced and the progress of the disease. This method 

 finally brings us a step nearer to solving the problem of the 

 significance of involution and degeneration forms of bac- 

 teria. 



COLOR-PHOTOGEAPHY. 



At the reading of a paper on '■ Chrome Photography in Prac- 

 tice," by Leon Vidal, before a recent meeting of the Photographic 

 Society of Great Britain, In London, a collection of photo- 

 mechanical pictures in color was shown, from different countries, 

 and made by different processes. According to the British Jour- 

 nal of Photography, the majority of the examples shown were 

 far in advance of anything of the kind produced heretofore. 



The journal mentioned goes on to say that the majority of the 

 pictures are produced by methods analogous to ordinary chromo 

 printing processes, inasmuch as different matrices are used for the 

 different colors. The printing plates or stones being made more 

 or less by the aid of photography, as an incentive to experiments, 

 in this direction, the journal indicates some of the methods by 

 which prints in color may be obtained, and probably the ways by 

 which the majority of those exhibited were made. 



In 1876 M. Ducos Duhauron patented a method whicli he termed 

 " photographs in colors." His method was to obtain three nega- 

 tives of the subject, one l)y green light, another by yellow, and a 

 third by violet light, by means of colored screens; aurine, eosine, 

 and clilorophyl being employed as different color sensitizers. 

 From the three negatives thus obtained prints were made on semi- 

 transparent media, prepared with Ihe complementary colors, and 

 then superimposed on each other. The late Mr. W.B. Woodbury 

 devised a process for producing prints in color. It was this. He 

 made a Woodbury print on paper which had previously had tho 

 appropriate colors printed upon it by lithography. By this process- 

 Leon Vidal, some years ago, produced some excellent work, and 

 evidently does so still, as proved by the specimens exhibited. 



Another plan is to take three or more negatives of the same 

 subject, and then stop out by hand in each certain portions repre- 

 senting the various colors, finally using these negatives to prepare 

 printing plates or stones for successive printings, as in the case of 

 chromo-lithography. By this system chromo-collotypes have long 

 been made. 



Messrs Goupil & Co. have for some years past been producing, 

 photogravures in colors in one printing from a single plate. The 

 method is this. The intaglio plate is inked in with different col- 

 ored inks applied locally as required. This method is a somewhat 

 tedious one, and necessarily requires considerable artistic skill on- 

 the part of the printer. Notwithstanding this, tlie firm have 

 shown many excellent examples from time to time in the exhibi- 

 tions of the Photographic Society. Instead of applying different 

 colored inks on the same plate, it is obvious that separate intaglio 

 plates can be prepared for the different colors and used for sepa- 

 rate printings. 



In his paper Leon Vidal alluded to the original method of su- 

 perimposing a Woodburytype in monocrome on paper printed with, 

 suitable colors by lithography, and also treating similarly printed 

 paper by imposing upon it a collotype print, as being the best in 

 practice. He also expressed the opinion that the claims, whichi 

 had been put forward by some, that the effects of nature could be 

 obtained by the photographic selective character of the negatives 



