isli 



THE GET^M AS A FRIEND IN 

 TIIEKAPEUTICS. 



(NOTES ON THE OPSONIC INDEX.; 



(BY EDW. J. ROBERTS, M.B.) 



During the last decade, the rapid 

 strides made in surgery are vv.ell-known 

 to the genert^l pnblic. It may be that the 

 attention i« ."O centred on that })ranch of 

 the "Art of Healing" that, in a measure, 

 the researches in medicine have not call 

 ed forth the notice which they cci'tainly 

 dieserv.e. The imp'ortant quest ioix of im- 

 munity is now attracting the attention ot 

 the wiiC'le medical worlil, brought to Ha 

 notice by the workerw in lijematolagy and 

 bacteriology. In all cases where the un- 

 welcome germ lakes a part, the physician 

 and bacteriologit-it must work together. 

 The busy physician has not the time to 

 comnlete his' invejtigatious of his case 

 further than tjie clinical aspect o" it, nor 

 has he the laboratory, instruments, etc., 

 neceissary to the close study of the action 

 of the germs causing that particular 

 disease which he lias under his care. Thy 

 bacteriolugist now informs the physiciiui 

 that th-ere 'is a proces.s by which one "s 

 able to pick out the defensive faebcTs of 

 the body, and to estimate their power of 

 d'e-struction over the inventing bacilli. Al- 

 thcaigh the process may not be taken over 

 by the physician, yet, with the help of thg 

 bacteriologist, he is able tO' nwre clearly 

 understand his patient's vital condition. 

 "We are indebted to Metchnikoff for point- 

 ing out some peculiar properties of cc'r- 

 tain wliite corpnsel-eiS^, ca- leucocytes 'n 

 the blood of man. These leucocytes have 

 the power of abi-orbing or destroying the 

 germs of disease under certain condi- 

 tions, and it is pointed out that tli.e>se con- 

 ditions can be so altered ?s to effect th;? 

 destroying property of the , leucocytes. 

 These leiicocytes, or white^ corpinscles, are 

 called phagocytes, and the process by 

 which they absorb the bacilli is named 

 phagocytosis. The blood serum has been 

 found to ocntain certain substances or 

 elements, to which the name "OpsO'nins" 

 was given — this ■word "O'psonin" ie from 

 the Lj.tin verb "opsono,"" meaning I cater, 

 or pi'iepai'e. Therefore, the opsonins) in the 

 serum prepare the germs in such a man- 

 ner as to render them an eaisy prey to the 

 phagocytes. It is suppO'Sied, and it is 

 probably the case, that the opsonins' act 

 by chemically nniting with the bacilli, 

 eo enabling the phagooires to render 

 them inert. In 1902, Major Leishman 

 published in the "British Medical Jonr- 

 naV an account of a practical method 

 whereby one can estimate the phagocytic 

 power of the white corpuscles of the 

 blcc'cl, and in following years Wright and 

 Douglas also wrote. This year. Dr. Mc- 

 Fariand and his confreres of Phila- 



delphia published to my mind a mu;h 



simpler i)r(>ces<<, wliich almost bring-s. iti 

 usage into the iiandi^. of the physician. I 

 will now come to the practical point of 

 estimating the ph.agocytic power of the 

 ieucoevtes. To quotrt- Dr. McFarland : "In 

 order to r-'f'i'lorm the experiment ,t is 

 necessary to have first the living phagocy- 

 tic cells; ,and, secondly, the bacteria they 

 are to take up, and it is necessary t<> 

 bring the-e two in contact under invari- 

 able conditions, in order that correct de 

 ductions concerning their interaction 

 may be drawn." Now, fii'st to secure the 

 cells. Make a small puncture in the fin- 

 ger of the patient at the I'oot of the finger 

 nail, draw a small quantity ot the blowl 

 that floiws in a pipett, made for the pur- 

 pose, or a capillary tube with evt i. 

 calibre. To prevent coagulation draw up 

 in the same pipett an exactly equal quan- 

 tity of a solution of citrate of SrO'iium, 

 IV ' ]jer cent. Now blow both fluids cm. a 

 clean slide, or better, in the depression 

 oiP the slide. Draw up and blow out 

 several times, until the fluidi-i are 

 thoroughly mixed. Now the blood is 

 ready for the particular germ yon wish 

 to experiment with. Now, an exactly 

 similar quantity (as the blood) of a stan- 

 dard emulsion of the bacteria is thorough- 

 ly mixed with the solution of blood and 

 citrate of sodium. This mixture of 

 blood, emulsion,, and citrate solution ^s 

 drawn up in a capillary tube, the ends 

 sealed, and the tube placed in an incu- 

 bator for thirty minutes. The tube is now 

 removed from the incubator, the ends 

 broken off, and the contents spread 

 on a clean slide, and allowed to dry. 

 The smear is then stained and counter- 

 stained, dried, and mounted in the usual 

 manner. The field should show the poly- 

 mwpho nuclear neutrophiles with their 

 nuclei and the bacilli stained according to 

 staining method used. The phagoej-tes axe 

 counted, ?nd the number of bacilli in 

 each also counted, and the average taken. 

 This number gives you the phagocytic m- 

 dex, and, dividing their number by the 

 standard yO'U have chosen, yon get the 

 Opsonic Index. This method, I hold, is 

 a much simpler one than that of Wright 

 and Douglasi. Wright and Douglas sepa- 

 rate the corpuscles with a centrifuge, 

 wash the corpuscles, and use patient s se- 

 rum. Now, one may well ask. What is 

 the use and value of finding the opsonic 

 index? It is to estimate the amount of 

 the particular vaccine required to in- 

 crease the patient's opsonic index, there- 

 by increpsing his power to resist attacks 

 of bacilli. If the experiment is carried 

 to a successful is.sue, and if the bacteri- 

 ologist can place in the hands of the 

 physician a simple -nxia-kable test, there is 

 no'doubt that Pasteur's hope will come to 

 be a fact. Pasteur prophesied that m 

 time to come all infectious diseases would 

 be treated and cured by vaccination, and 

 when we review the past tivelve years, w© 



