SCIENCE 



[N. S. Vol. XXXIX. No. 1013 



The Malarial Parasites: Maey R. Law son, M.D. 



Many of the misconceptions in regard to the 

 morphology and biology of the malarial parasites 

 are due to the fact that the majority of observers 

 have believed them to be intracellular, and that 

 each parasite grew up and completed its life cycle 

 within a single corpuscle, the segmentation of the 

 parasite corresponding to the final destruction of 

 the corpuscle. The writer believes the parasites to 

 be extracellular throughout .''eir existence, that is, 

 when not in migration, they attach themselves to 

 the external surface of the red corpuscles by 

 means of protoplasmic pseudopodia surrounding 

 mounds of corpuscular substance, which the para- 

 site has "squeezed up" for the purpose of at- 

 tachment. This interpretation is confirmed by 

 seeing the corpuscular mounds at the periphery of 

 the red corpuscles encircled by the pseudopodia of 

 the parasites. 



The evidence in favor of migration is: 



1. The destiaiction of red corpuscles is usually 

 out of all proportion to the number of parasites 

 present, providing one parasite destroys but one 

 corpuscle. 



2. In multiple infection of red corpuscles by sev- 

 eral young parasites, they can not all grow up on 

 one corpuscle, therefore they must migrate or die. 



3. Stages of parasitic migration such as (a) 

 Free pigmented parasites, compact, amoeboid, with 

 pseudopodia. (6) Pigmented parasites attached 

 to apparently healthy corpuscles, (c) Pigmented 

 parasites (24 hr.) apparently in the act of aban- 

 doning degenerated corpuscles, (d) Parasites on 

 corpuscular skeletons, (c) Corpuscular skeletons 

 which are expanded remnants of red corpuscles 

 which have been dehemoglobinized. 



The sexual cycle takes place in the blood of man 

 in the various malarial infections. The flagella 

 are always derived from the chromatin substance, 

 and from the chromatin alone. In the £estivo-au- 

 tumnal infections the writer has observed but one 

 flagellum to each crescent, while in the tertian and 

 quartan infections, there are several flagella to 

 each parasite. 



A Preliminary Comrminication on the Etiology of 

 Pycemia Arthritis in Foals: Frank W. Scho- 



FIELD. 



The author after a brief discussion relative to 

 modes of infections points out that intrauterine 

 infection of foal can alone account for some cases, 

 and most probably does for more than is generally 

 believed. The bacteriology of the disease is re- 

 viewed and author's findings given. An organism 

 of the colon typhoid group has been recovered un- 

 contaminated from blood and joints in early stages 

 of disease. The relationship of this organism to 



the disease was established by complement fixation 

 tests using foals ' blood and organism isolated as 

 antigen. Positive fixation tests were also obtained 

 from the blood of dams that have delivered foals 

 which subsequently became diseased. 



Experiments Bearing on Pulmonary Infection: 

 Frank W. Schofield. 



Mention is made of two existing views regard- 

 ing pulmonary infection. That it is due to direct 

 inhalation of course into smaller air passages, or 

 arises as the result of a primary infection of blood 

 stream. The diffi-Culty of infecting the lung by 

 direct inhalation was demonstrated by experiments 

 of following nature. 



First Experiment. — Horses were exposed to a 

 very fine spray from powder atomizer, the material 

 used being equal parts gentian violet and powdered 

 charcoal. After a few minutes' spraying the at- 

 mosphere became saturated with this fine violet 

 powder. Horses breathing normally filtered all the 

 powder out of the inspired air before same reached 

 trachea. When excessive, labored and rapid 

 breathing was induced the powder could be de- 

 tected in ^ the larger bronchi. 



Second Series of Experiments. — A spray of B. 

 prodigiosus was here substituted for the powder. 

 The spray was manipulated so that the fine termi- 

 nal portion of the same enveloped the nostrils of 

 animals breathing it. The spray was kept up for 

 several minutes. In most cases the organism could 

 not be recovered past the larynx. When present 

 in the trachea bacilli were few in numbers. The 

 last experiment consisted of taking a number of 

 swabs from the trachea of normal horses, cattle, 

 sheep. In most cases the tracheae were found to be 

 sterile. When the organ was infected the organ- 

 isms were S. aureus, S. alMis and Streptococci. 

 None of the common organisms present in the air 

 these animals were breathing were recovered from 

 the trachea. 



Conclusions. — ^In health the trachea if not sterile 

 has no constant bacterial flora. This could not be 

 so if dust with bacteria could easily pass the naso- 

 pharynx. 



That with nasal breathing most of the bacteria 

 inhaled are removed before the air enters the 

 trachea, even when the atmosphere is saturated 

 with bacteria. 



That direct infection of lung through nasal in- 

 spiration is almost impossible, under ordinary con- 

 ditions. 



A. Parker Kitchens, 



Secretary 



