Method of Disintegrating Bacterial Cells, 



57 



subsequent inoculation with the corresponding living organisms, a protection 

 which, with appropriate doses of the endotoxin, is exerted for at least 

 11 weeks after the injection of the endotoxin. This result suggests that 

 endotoxins may be of considerable value as protective or prophylactive 

 vaccines. The endotoxin solutions maintain their activity for at least six 

 weeks. 



A few inoculations of typhoid and diphtheria endotoxins have been 

 performed iu the human subject. The inoculations cause some local reaction 

 at the site of inoculation, consisting of redness, soreness and stiffness of 

 the part, but little general reaction is induced, nor are any ill effects 

 apparent. 



I am indebted to Mr. Henry Wellcome for the facilities he has kindly 

 afforded me for carrying out this work at the Wellcome Physiological 

 Laboratories, and my best thanks are due to Mr. E. Thompson for his 

 invaluable assistance in the preparation of the endotoxins. 



On a Method of Disintegrating Bacterial and other 

 Organic Cells. 

 By J. E. Barnard and B. T. Hewlett. 



(Communicated by Prof. W. D. Halliburton, F.E.S. Received March 28, — Bead 

 May 4, 1911.) 



[Plate 1.] 



The methods hitherto available for accomplishing the disintegration of 

 bacteria may be summarised briefly as follows : — The earliest experiment is 

 that of Buchner* for obtaining the intracellular juices of yeast. This 

 method was adopted by Macfadyen, Harris-Morris, and Bowland in their 

 investigations on " Expressed Yeast Cell Plasma," communicated to the Boyal 

 Society, June 19, 1900, but they subsequently introduced some modifications 

 and improvements in the method. 



Their improved process was to place the yeast cells in mass in a mechanical 

 contrivance, together with a proportion of added silver sand, and to violently 

 agitate the containing vessel. The rapidly succeeding impacts of the yeast 



* 'Berichte d. Deutsch. Chern. Ges.,' 1897, p. 117, and succeeding papers, 1897-1900. 



