NOTES AND MEMORANDA. 



237 



in question was judged of by the degree of dilution to which, it could 

 be subjected without losing its power of destroying life. The results 

 are stated by him as follows : — Ordinary blood kept at a temperature 

 of about 100° Fahr. becomes so virulent in forty-eight hours, that 

 a trillionth of a drop, injected subcutaneously, is enough to kill a 

 rabbit. 2. The blood of a person affected with certain febrile 

 diseases, particularly typhoid fever, possesses a similar activity. Of 

 the numerous experiments related, in which rabbits were killed with 

 quasi infinitesimal doses of typhoid fever blood, it may be useful to 

 reproduce one — the last of the series — as an example of the rest. In 

 a case of typhoid fever, blood was taken at various periods during the 

 progress of the disease ; the plan followed being to inject, at each 

 period, blood of two dilutions subcutaneously into two test-animals, 

 of which one received T oVo drop, the other roo"wo o drop. When 

 this was done at the eighth day of the disease, the first rabbit sur- 

 vived seven days ; the second, twenty-seven days : at the eleventh 

 day, the first rabbit survived seven days; the second, three and a 

 half days : at the sixteenth day, the first survived eleven days ; the 

 second, twenty-five days. After complete convalescence the experi- 

 ment was repeated. Neither of the test rabbits was in the slightest 

 degree affected. 



NOTES AND MEMOEANDA. 



A New Slide for the Microscope. — At a recent meeting of the 

 Optical section of the Franklin Institute, U.S.A., there was described 

 and exhibited in operation a new adjunct to the microscope, designed 

 by Mr. D. S. Holman, a member of the Section, whose life-slide 

 recently attracted so much attention and comment. The new device 

 may be called a current cell, or moist chamber, and is designed to 

 afford the microscopist the opportunity of observing and studying the 

 constitution of the blood and other organic fluids with much greater 

 ease and precision than it has heretofore been found possible to 

 attain. The accompanying illustration will serve to make the descrip- 

 tion of its construction and operation manifest : — 



The slide consists of a plain piece of plate glass of considerable 

 thickness, and three inches by one in dimensions. 



