THE PROGRESS OF SCIENCE 



95 



Edwin G. Conklin of the University of | for phagocytosis. The method of de- 

 Pennsylvania, Dr. D. T. MacDongal of 

 the Carnegie Institution, Mr. Charles 

 A. Conant of New York City, and Dr. 

 Simon Flexner of the Rockefeller In- 

 stitute for Medical Research. 



Most of the meetings will be held at 

 Columbia University, but there will 

 also be sessions at the American 

 Museum of Natural History, The 

 Rockefeller Institute for Medical Re- 

 search, the College of the City of New 

 York, the New York Botanical Garden 

 and elsewhere. These and other scien- 

 tific institutions of the city have in 

 recent years made extraordinary prog- 

 ress. There is here only space to show 

 several of the buildings of Columbia 

 University, which, having removed to 

 its new site overlooking the city of 

 New York only ten years ago, has 

 now a group of academic buildings in 

 many respects unequalled. 



THE OPSONIC INDEX OF WRIGHT 

 AND DOUGLAS 

 Sir Almroth E. Wright, M.D., 

 F.R.S., pathologist to St. Mary's Hos- 

 pital, London, and late professor of 

 pathology, Army Medical School, Net- 

 ley, delivered the third course of lec- 

 tures on the Herter foundation in the 

 Physiological Building of Johns Hop- 

 kins Medical School on October 8, 9 

 and 10, 1906. The subject chosen was 

 ' The therapeutic inoculation of bac- 

 terial vaccines and its application in 

 connection with the treatment of bac- 

 terial disease.' As this subject is an 

 important elaboration of Metchnikoff's 

 work upon phagocytosis and of Ehr- 

 lich's side-chain theory, it may not be 

 out of place briefly to outline from 

 these lectures Wright's method and to 

 cite a few illustrative cases showing 



termining the opsonic index is as fol- 

 lows: About five cubic centimeters of 

 blood is withdrawn from a healthy per- 

 son under aseptic conditions by prick- 

 ing the finger. This blood is then placed 

 in a glass tube (A), slightly heated to 

 facilitate clotting, and centrifugalized 

 so as to separate the serum from the 

 clot. In a second tube (B) is placed 

 about the same amount of blood, to 

 which is added sodium-citrate solution 

 in order to prevent clotting. By cen- 

 trifugalizing this there are obtained 

 three layers, i. e., serum, white cor- 

 puscles and red corpuscles. The serum 

 it pipetted off and the solution contain- 

 ing leucocytes at once becomes easi'y 

 accessible. A third tube (C) contains 

 an aqueous solution of tubercle bacilli. 

 This is also centrifugalized in order to 

 get a fine suspension. Equal quanti- 

 ties of the serum of a healthy person 

 (A) ; of white blood corpuscles (B) ; 

 and of a tubercle bacilli solution (V) 

 are drawn into a capillary tube and 

 freely mixed. They are then placed 

 in an incubator for twenty minutes. A 

 film is next made and stained by any 

 cf the well-known methods of staining 

 for tubercle bacilli. Then the exact 

 number of bacilli found to be present 

 in thirty consecutive multinuclear leu- 

 cocytes are counted by the aid of an 

 oil-immersion lens — call it in this case 

 X. The process is now repeated, sub- 

 stituting the blood of a patient for the 

 blood of the healthy person, the white 

 corpuscles and aqueous tubercle solu- 

 tion remaining constant in both esti- 

 mations. The result obtained by count- 

 ing these latter may be called Y; in 

 that case the opsonic index of the pa- 

 tient's blood is expressed thus, Y/X, 

 which is usually a decimal. The en- 



the value of this mode of procedure in tire process occupies about one hour 



the treatment of certain bacterial dis- and a quarter in the hands of an expe- 



eases by vaccines. rienced laboratory worker. 



The term opsonin, meaning ' to pre- The surgeon's idea of curing bac- 



pare for a meal,' is given to a recently terial diseases, such as scrofulous 



discovered and important constituent glands of the neck, seems too often to 



of both normal and immune sera, by be that of extirpation, though he does 



means of which bacteria are prepared often employ instead of the knife 



