RESEARCH SEMINAR. 24! 



the tissue coagulins attack the fibrinogen directly and transform 

 it into fibrin. That this actually does take place I believe to 

 have been able to show in the invertebrate blood (lobster), inso- 

 far as tissue coagulins still cause the coagulation of the blood 

 plasma, after the substances present in the blood which accelerate 

 the coagulation of the blood have been previously destroyed by 

 heat. 



It seems permissible to apply this result to vertebrate blood, 

 the similarity between the factors causing the coagulation of ver- 

 tebrate and invertebrate blood being very great. 



In connection with the foregoing experiments a comparative 

 study of the conditions under which these two substances act 

 was made (influence of dilution, of calcium and other salts, power 

 of resistance, preparation of active extracts). Their action on 

 artificially prepared fibrinogen was also compared. 



New facts were found which support the view formerly ex- 

 pressed that the coagulation of other arthropods represents an 

 agglutination of the blood cells. In accordance with this view, 

 I could prepare fibrinogen from lobster blood, in which a second 

 coagulation takes place. On the other side, no fibrinogen could 

 be prepared from Liinnlus blood, which has no second coagulation. 



2. BOTANICAL LECTURES AND SEMINARS IN 1903. 



July 8, Dr. George T. Moore : " The Polution of Public Water 

 Supply by Algae." 



July 10, Dr. Bradley M. Davis: "The Relationships of the 

 Sexual Organs of Plants." 



July 20, Dr. Henry Kraemer : " The Unorganized Contents 

 of the Plant Cell." 



July 21, Dr. Henry Kraemer: "The Structure of the Cell 

 Wall." 



July 27, Mr. Herbert J. Webber : " History and General Fac- 

 tors of Plant Breeding." 



July 28, Mr. Herbert J. Webber : " The Principles of Selec- 

 tion and Isolation in Improving Breeds." 



July 29, Mr. Herbert J. Webber : " The Mutation Theory of 

 De Vries." 



July 30, Mr. Herbert J. Webber : " The General Laws of 

 Hybrids with a Discussion of Mendel's Principles." 



