The nervous system in the Cestode Moniezia expansa. 361 



(luring the progress of my study — that of keeping the worms alive 

 and constantly at hand for use in the laboratory. Although material 

 was abundant at the abattoir, it required considerable time and trouble 

 to obtain it, and when working with methylen-blue it was absolutely 

 necessary to have a constant supply of living material. As the 

 methods given by Lönnberg for this purpose were a failure, as far 

 as this species was concerned , considerable time was spent in ex- 

 perimenting with different mixtures and methods for keeping the 

 worms alive. 



I. Material and Methods. 



A. Material. 



Abundant material from the small intestine of Ovis aries was 

 obtained as needed from the abattoirs of Boston. The cestodes 

 Moniezia expansa were taken from the intestines shortly after the 

 animals were slaughtered and before the viscera became cooled. It 

 was found best to visit the abattoir early in the morning soon after 

 work had commenced, as one was then sure of being able to examine 

 the viscera before they became cool, or had suffered from lying in 

 heaps in the "gut room", or from the rough handling which often 

 destroys the larger and more desirable specimens. 



In removing the worms it was found undesirable to slit open the 

 intestine, but much better to sever it near the beginning of the coecum, 

 then, beginning at the pylorus, slowly to "strip" the intestine between 

 the thumb and forefinger, causing the contents to flow from the cut 

 end. In parasitized animals the greater number of worms were found 

 in the ilium, or caudal portion of the intestine, a few in the jejunum, 

 and only occasionally one in the duodenal region. Although this 

 method of removing the worms was not all pleasant, it was rapid and 

 practical. Moreover, by this method, the worms could be removed 

 not only in a more satisfactory and less broken condition, but more 

 easily and rapidly, and without exposing them to the air as long as 

 in the process of opening the intestine longitudinally. In almost every 

 case where the worms were removed in this manner the scolex came 

 away with the proglottides. Moreover, the scolex was not injured in 

 any way by this treatment, as the worms evidently relax their hold 

 upon the intestinal wall; whereas, if the intestine was slit open and 

 the worms taken out, they invariably held tightly to the wall, and 

 could be removed only by being pulled or cut away. This resulted 



24* 



