THE MALARIAL PARASITE, 641 



the pustules of variola and in vaccine lymph lias been reported 

 by several investigators: Guarnieri (1892), Monti (1894), Plana 

 and Galli-Valerio (1894), L. Pfeiifer (1894), Clarke (1895), von 

 Sicherer (1895), E. Pfeift'er (1895). Guarnieri in 1892 published a 

 paper in which he claimed to have cultivated the amoeboid micro- 

 organism found by him in vaccine lymph by successive inocula- 

 tions in the cornea of rabbits. E. Pfeiffer has since (1895) con- 

 firmed this observation, and has seen the parasite undergoing 

 amoeboid movements and in progress of multiplication by spon- 

 taneous fission. During the past two years investigations relating 

 to the aetiology of vaccinia and variola have been made at the 

 Army Medical Museum in Washington, by Major Walter Reed, 

 surgeon United States Army. These investigations show that in 

 vaccinated monkeys and in children an amoeboid parasite makes 

 its appearance in the blood on the sixth or seventh day after vac- 

 cination, and may be found during a period of from five to seven 

 days, when it disappears. Reed has found the same parasite in 

 the blood of patients with variola and in his own blood after an 

 accidental vaccination in the finger. The parasites are not nu- 

 merous. They are less than a third the diameter of a red blood- 

 corpuscle, and may be observed to undergo amoeboid movements 

 in a drop of blood, properly mounted for microscopical examina- 

 tion, during a period of twenty-four hours or more. These amoe- 

 boid bodies, like the malarial parasite, would be easily overlooked 

 by one not an expert in blood examinations. 



The presence of a ciliated amoeboid micro-organism in the mu- 

 cous secretion coughed up by children suffering from whooping- 

 cough has recently been reported by Deichler and confirmed by 

 Kourlow. This may prove to be the cause of the disease, but 

 further researches will, of course, have to be made before this can 

 be determined. In view of the extended investigations made dur- 

 ing the past few years by competent bacteriologists, it seems prob- 

 able that in most of those infectious diseases in which the specific 

 infectious agent has not yet been discovered it belongs to some 

 other class of micro-organisms than the bacteria ; and it seems 

 not improbable that some of them at least will prove to be due 

 to infection by "germs" belonging to the class to which your 

 attention has been invited in the present address viz., the patho- 

 genic protozoa. 



M. Henri de Kerville describes fifteen yew trees in Normandy which 

 are supposed to be a thousand years old and more ; a number of oaks from 

 three hundred to nine hundred years old ; cedar trees from a hundred to a 

 hundred and fifty; a hawthorn, two hundred; a pear tree, more than a 

 hundred ; a holly tree, a hundred or a hundred and fifty ; and an American 

 tulip tree, a hundred or a hundred and twenty years old. 



VOL. L. 48 



