BY N. A. COBB. 171 



swallowed it. This capsule for some reason I never recovered, 

 and this fact led me to abstain from repeating the experiment 

 until it became certain that no evil eflects resulted. After 

 waiting about a year I became convinced that in the disagreeable 

 search for the capsule I must have overlooked it. In my second 

 experiment therefore I took precautions to insure an early 

 recovery. Obtaining at last a fresh supply of eggs, I swallowed 

 another similarly prepared capsule after having partaken of a 

 liquid dinner. This was at 7 p.m. At 2 a.m., I took a dose of 

 castor oil, and at 7 a.m., recovered the capsule by means of a long 

 handled paint brush and a sieve whose meshes were just small 

 enough to intercept the capsule. On breaking the capsule I 

 found the embryos hatched and in active motion. The eggs used 

 in this experiment were freshly laid and contained embryos in the 

 so-called tad[)ole stage. The results of this experiment led me to 

 make a third, in which I used a large number of eggs containing 

 fully developed and, when warmed, actively moving larvjB. This 

 third capsule was swallowed at IQi p.m., and recovered, by 

 purging, at a little before 4 a.m. It remained in the alimentary 

 canal in all less than six hours. On opening the capsule 

 on a warm stage I received a large number of actively moving 

 larva^ which I at once killed, a part 'with hot solution of corrosive 

 sublimate and the remainder with yVVo osmic acid and brought 

 respectively into Canada balsam and glycerine by means of the 

 difterentiator.* The results of experiments two and three I will 

 now detail in full. 



Experiment II. 



Nearly all the eggs used (12-13) hatched. Most of them had 

 undergone some development, moi'e in fact than the remaining 

 eggs out of the same lot which lay meanwhile in the dead and dry 

 female worm, but not so much as might have been expected. The 



* For description see "Two new instruments for biologists," Cobb I.e. 

 Also British Association for the Advancement of Science, " Report (1SS9) 

 on the Zoological Station at Naples." 



