428 Gary N. Calkins. 



which accompanied depression at this period. The dense con- 

 dition of the protoplasm is better shown in Fig. 6 which represents 

 an individual twenty-four hours after transference from beef 

 extract into hay infusion. It may be noted here that, at this 

 period, the beef extract failed to reduce the dense endoplasmic 

 condition to one of tenuity which seems to be the normal 

 condition. 



b. Extract of Pancreas. Extract of pancreas was made in the 

 same way as the beef extract. A fresh sheep's pancreas was Gut 

 in small pieces and brought to boiling point in water. After 

 filtering and cooling, the Paramoecia were placed in it and left for 

 24 hours, as in the beef. At first it proved a good substitute for 

 the beef and the organisms appeared to thrive on it; but later, in 

 November and December, it was as useless as the beef. The 

 following records show this fact: 



June 27. A3 treated. Divided twice in 24 hours. Forms 



the regular series from this time. 



June 29. Ai and A2 " Divided a few times. Died out 



on July 14. 



July 16. A4 " Died the next day without divi- 



sion. 



July 17. A6 " Divided twice the next day; lived. 



July 18. Ai,A2 and A4 " All died the next day. 



July 20. Ai,A2andA4" Lived. Given mutton broth on 



23d. Died on 24th. 



Aug. 20. A2 " Died on 28th. 



Aug. 20. A8 " Died on the 2ist. 



Dec. 8. A5, A6, A7 and A8 treated. No divisions. All died out 



on 19th before or after treatment with various other substances. 



At the period in June when recovery was effected by using the 

 extract of pancreas, the organisms of both series were in the con- 

 dition represented by Fig. 7. The endoplasm was densely granular 

 and homogeneous, and had a curiously "stuffed" appearance. 

 This condition was relieved by using extract of pancreas, whereas 

 beef extract, made with the same water and in the same way, was 

 ineffectual. Figs. 8, 9 and 10 show the general course of the 



