Nov. 25. 1918 Observations and Experiments on Intestinal Trichince 469 



of which was too small to admit the coarser intestinal debris. The organ- 

 isms were transferred to a 0.7 per cent solution of sodium chlorid in a watch 

 glass which could be mounted on the stage of the microscope in order to 

 make observations. To make out details slide preparations were made. 

 When it was desired to keep the parasites in the laboratory overnight they 

 were transferred by means of the pipette to a second watch glass in order 

 to get rid of as much intestinal debris as possible. If this precaution 

 is not taken putrefaction may set in, which, besides causing an offensive 

 odor, forms a film on the surface and interferes with the observations. 



Unless otherwise stated the parasites were kept in a 0.7 per cent 

 solution of sodium chlorid which will be referred to as a physiological 

 salt solution. In the description of the experiments and observations 

 reference is made to the time which elapsed between the feeding of the 

 trichinous meat to the host and the isolation of the parasites from the 

 intestine. Inasmuch as albino rats do not as a rule eat the meat as soon 

 as it is offered to them allowance must be made for the intervening period, 

 which may vary from a few minutes to several hours. 



MIGRATION OF THE LARV^ FROM THE STOMACH TO THE INTESTINE 



When trichinous meat is fed to a suitable host the cysts are digested 

 in the stomach, the larvae becoming free in the lumen. The following 

 observations point to the conclusion that the decapsuled larvae do not 

 linger in the stomach but make their way into the small intestine very 

 promptly after their liberation from the cysts. Furthermore, to judge 

 from their behavior in vitro, it appears highly probable that their own 

 muscular movements aid them in this change of location. 



When the stomach still contains trichinous meat in various stages 

 of digestion few decapsuled larvae are found in it, although the small 

 intestine may contain many newly arrived parasites. The latter may 

 still be tightly coiled and, therefore, probably unattached to the mucosa. 

 Within four hours after feeding trichinous meat, a number of tightly 

 coiled larvae were found in the intestine, but none were seen in the stomach. 

 Eighteen hours after feeding, the small intestine was found to contain 

 numerous parasites, some attached to the mucosa and active, others 

 still unattached and coiled, the latter l5dng free in the lumen. The stomach 

 contents of such hosts were usually found to be free from parasites. 

 Feeding trichinous meat in which the parasites are no longer alive or 

 so reduced in vitality as a result of refrigeration or other means of 

 attenuation that they fail to survive the action of the gastric juice, 

 does not result in a rapid transfer of the larvae from the stomach into the 

 intestine. Within about 18 hours after feeding such meat numerous 

 larvae were found in the stomach. The parasites were uncoiled and 

 inactive and somewhat paler than larvae known to be alive. In the 

 small intestine the parasites were found in various stages of digestion. 



