PROFESSOR TYNDALUS RECENT RESEARCHES. 687 



would be found to go hand in hand. He thought the simple expedient 

 of examining by means of a beam of light, while the eye was kept 

 sensitive by darkness, the character of the medium in which their ex- 

 periments were conducted could not fail to be useful to workers in 

 this field. But the method has not been much turned to account, and 

 this year he thought it worth while to devote some time to the more 

 complete demonstration of its utility. 



He also wished to free his mind, and if possible the minds of 

 others, from the uncertainty and confusion which now beset the doc- 

 trine of " spontaneous generation." Pasteur has pronounced it " a 

 chimera," and expressed the undoubting conviction that this being so 

 it is possible to remove parasitic diseases from the earth. To the 

 medical profession, therefore, and through them to humanity at large, 

 this question is one of the last importance. But the state of medical 

 opinion regarding it is not satisfactory. In a recent number of the 

 British Medical Journal, and in answer to the question, " In what 

 way is contagium generated and communicated ? " Messrs. Bi-aidwood 

 and Yacher reply that, notwithstanding " an almost incalculable 

 amount of patient labor, the actual results obtained, especially as 

 regards the manner of generation of contagium, have been most dis- 

 appointing. Observers are even yet at variance whether these mi- 

 nute particles, whose discovery we have just noticed, and other dis- 

 ease-germs, are always produced from like bodies previously existing, 

 or whether they do not, under certain favorable conditions, spring 

 into existence de novo.'''' 



With a view to the possible diminution of the uncertainty thus de- 

 scribed, he submitted without further preface to the Royal Society, and 

 especially to those who study the etiology of disease, a description of 

 the mode of procedure followed in this inquiry, and of the results to 

 which it has led. 



A number of chambers, or cases, were constructed each with a 

 glass front, its top, bottom, back, and sides being of wood. At the 

 back is a little door, which opens and closes on hinges, while into the 

 sides are inserted two panes of glass, facing each other. The top is 

 perforated in the middle by a hole two inches in diameter, closed aii-- 

 tight by a sheet of India-rubber. This sheet is pierced in the middle 

 by a pin, and through the pin-hole is passed the shank of a long 

 pipette ending above in a small funnel. A circular tin collar, two 

 inches in diameter, and one inch and a half high, surrounds the pi- 

 pette, the space between both being packed with cotton-wool moist- 

 ened by glycerine. Thus, the pipette, in moving up and down, is not 

 only firmly clasped by the India-rubber, but it also passes through a 

 stuffing-box of sticky cotton-wool. The width of the aperture closed 

 by the India-rubber secures the free lateral play of the lower end of 

 the pipette. Into two other smaller apertures in the top of the case 

 are inserted, air-tight, the open ends of two narrow tubes, intended to 



