xlii 



cajinot but be convinced that this will b© 

 <Kir method in the .near fitture. I may 

 here briefly describe the method of ob- 

 taining the vaccines.. The vaccine con- 

 sists Tvf an emulsion of the particular 

 germ which causes the disease which one 

 is treating. Large growtJie of ycung cul- 

 tures are grown on a medium, princi- 

 pallv Agar, and when ready are washed 

 off the agar with wa'rm salt solution. Th s 

 is now thoiroughly shaken up in a test 

 tube to separate the bacilli and to break 

 dmvn th© clumps. A centrifuge does the 

 work of separating very quickly ; it isi a 

 verv tedious process to get the emulsion 

 to the proper standard. By coauparing 

 the number .cf red corpuscles vrith a nujn- 

 ber of germs in a given quantity of fluid, 

 one can estimate the number of germs 

 very readilv. Take a mixture of one part 

 emulsion, pone part bloo'd, and three-parts 

 saline isolution, and count both corpuscles 

 and germs in a given spaice. Therefore, 

 siipposing there were ten times the num- 

 ber of germs as there were corpuscles, we 

 should have 45,000, 0'OO in one cubic milli- 

 metre. Now we come to^ the method of ap- 

 plying the treatment. First of all, you 

 diagnose the disease, take the opsonic in- 

 dex of vour patient, and have your vac- 

 cine. The patient is now given his injec- 

 tion of warm vaicciue, and his opsonic in- 

 dex watched very carefully. A shoi't time 

 after the injection the opsonic index falls, 

 and this stage is called the "negative 

 phase." After a time, from a' few houi'S 

 to two or three days, the opsonic index 

 rises again, and this stage is called the 

 "positive phase. " In time the index clim- 

 inishes. and another injectiH3.n is required, 

 but this time the "negative phase" 

 should be much shorter than the first. 

 Then, again, the index rises, and may 

 reach or even go higher than the normal. 

 Repeat the infection until the opsonic in- 

 dex remains at the normal. Never give 

 the vaccine during the "negative phase." 

 What goes on in the patient during this 

 treatment is, first, the iopsonins are in- 

 creased and the phagocytosis is improved, 

 and, secondly, the bacilli .axe destroyed, 

 and the infection ceases, and a cure is 

 recorded There is no. doubt whatever 

 that performing the experiment is not so 

 easy as one would im.agine from merely 

 reading an account of it. The difficulty 

 of standardising the emulsion and the 

 grtiidiug and separating the bacilli re- 

 quire a lot of practice and care. The de- 

 calcif ang the blood and the mixing of 

 the fliiids) is simple enough, but it is ra- 

 ther a delicate and difficult job to fix and 

 gtain the smear satisfactorily. "Opso- 

 nin" is the sauce which is mixed_ Avith 

 the bacteria to increase the appetite of 

 the phagocytes. I mentioned immunity 

 in the beginning of these notes. Immu- 

 nity is really the power of resisting the 



attacks of any given germ or disease. 

 This immunity may be either natural or 

 may be produced by artificial means. To 

 render my meaning more clear, I will 

 take the disease small-pox, of whicli we 

 have had quite encngh experience in this 

 State Some per>on© were naturally im- 

 mune against this disease, while otheis 

 readih fell victims to the small-pox ba- 

 cilli. To prevent the spread o^f this dis- 

 ea,-e, we artificially rendered people_ im- 

 mune by giving tiiem the disease in a 

 verv liiild form by vaccination. It was 

 not" actually the mild disease which we in- 

 troduce that caused the immunity, but 

 the products o^f bacterial action formed 

 during its course. So, by thes3 bacterial 

 prrducts, are produced various degrees of 

 immunity withont ciausing any disturb- 

 ance to the patient in the majority of 

 cases. Of course, an attack of th© disease 

 small-pox itself causes a much higher de- 

 gree of immunity, anid is more lasting 

 than that caused' by vaccination. It has 

 been discovered that the serum of a high- 

 ly-immunised animal when injected into 

 a second animal will protect that second 

 animal more or less from an attack of 

 the given bacteria. Now, this serum from 

 the highly-immunised animal is called 

 anti-toxin, and one particular anti-toixin 

 was used only recently in the slight out- 

 break of diphtheria in this city. Al- 

 though all the .'^era have not been so suc- 

 cessful as the anti-toxin of diphtheria, 

 yet still I am certain, as the researcheg 

 continue, we may be sanguine that 

 they will be so. With reference 

 to ' th© phag'Gcytic action of the 

 leucocytes, we endeavour to increase that 

 action' by the injection of the bacterial 

 products" of the given germ. Let us take 

 a caye of consumption or tuberculosis — 

 unhappily, we have not far to go for ex- 

 amples — would it not be a blessing to all 

 if we could destroy the tubercle bacilli by 

 increasing the phagocytic power of the 

 leucocytes *by the simple means of injec 

 tions of a serum? The delicate and most 

 interesting process of finding the opsonic 

 index, which I have endeaAoured to ex- 

 plain tO' you to-night, may be hailed as 

 another fighting factor against the dread- 

 ful disease tuberculosisi. What physician 

 would dare neglect to give the anti-toxin 

 of diphtheria in a cai^e of diphtheria at 

 the pretient time if it v,-ere procurable ? 

 The same question will be asked in the 

 future concerning other anti-toxins. The 

 discovery of the phagocytic power of the 

 leuco'cytes has caused workers all over 

 the world to endeavour to make the test 

 simple, and give a. practical therapeutic 

 value to it. I trust these few remarks 

 will be underston^d, so that the public will 

 be prepared in some measure for the prac- 

 tical working of this new curative agency. 



