438 



APPENDIX, 



Concerning Magnifying Powers. 



IN order that some idea may be formed of the degree of 

 magnifying power of the one-fiftieth of an inch object glass, 

 lately made for me by Messrs. Powell and Lealand, it may 

 be stated, that if it were possible to see a human hair in its 

 entire width under this power, it would appear to be nearly 

 one foot in diameter, and an object an inch in height would 

 be made to appear 250 feet high. 



Dr. Lewis's Observations on Hallier's Cholera Fungus. 



Since the first sheets of this work were printed, I have 

 received from Calcutta, through the kindness of the author, 

 a copy of the "Report on the Microscopic Objects found 

 in Cholera Evacuations, &c.," by Assistant-Surgeon Lewis, 

 M.B., attached to the Sanitary Commissioner with the 

 Government of India. By a series of most careful micro- 

 scopic investigations it is proved for once and for all, that 

 Hallier's views on cholera are erroneous. His cholera 

 fungus is not peculiar to cholera stools. Dr. Lewis's Report 

 is illustrated by nearly a hundred very careful drawings, 

 exhibiting points of great interest and importance. Every 

 one studying the subject of disease germs should see this 

 . Report. Some of the questions referred to in the first part 

 of my work are considered with great care, and several of 

 the conclusions at which I have arrived receive support 

 from Dr. -Lewis's observations. To the correctness of his 

 drawings, and remarks upon Bennett's and Pouchet's state- 

 ments (p. 48 of Dr. Lewis's Report), I can bear testimony. 



Bioplasm and the Contact Theory. 



For a general statement of the nature of morbid poisons 

 and the growth and changes occurring in bioplasm in 



