1895 



THE MICROSCOPE. 



85 



florescent needles. The slide from winch the one shown 

 below was taken gave many needles and detached crys- 

 tals arranged similarly to the small ones in the part giv- 



oo 



^^:^ 



en. There were several as large or larger than the 

 largest part shown. It polarizes well. 



Two salts may sometimes be combined with good 

 results. 



Diptheria Aiiti-toxine. 



By C. HADLEY CARLSON, M. D., 



SAN FRANCISCO, CAL. 



[Report of au address before the San Francisco Microscopical Society, 

 April i6, 1895 by Wm. B. Loy, Secretary.] 



Anti-toxine is a preparation from the blood serum of 

 a perfectly healthy horse, into whose circulation has been 

 injected the toxine of diptheria. It has long been known 

 that patients who have recovered from infectious disea- 

 ses exhibit a greater or less degree of immunity to future 

 attacks ; and for centuries it has been the custom to arti- 

 ficially infect with genaine smallpox, which running a 

 comparatively light course, rendered the person so trea- 

 ted proof against future attacks of fierce epidemics. 

 Vaccination, as now administered, consists in inoculation 

 with an attenuated or modified form of the agent that 

 causes variola. The discovery of vaccination is the 



