49© 



AMERICAN JOURNAL OF BOTANY 



[Vol. 8, 



Austrian pine, dock, daisy, goldenrod, ragweed, rye, and timothy pollens 

 were tested with the different substrates for lipase. The tests with ethyl 

 butyrate were unsatisfactory. In the olive oil emulsion and methyl acetate 

 media, Austrian pine, dock, ragweed, and rye pollens gave positive tests 

 for lipase. The action on methyl acetate was especially marked with Aus- 

 trian pine pollen, in which case the titrations showed nearly double the 

 amount of acid with fresh pollen as compared with the boiled control. 



Tests for Proteolytic Enzymes 



Substrates for Proteolytic Enzymes 



i. Blood fibrin. Fresh fibrin from pig's blood was obtained at the 

 slaughter house, and was washed for several hours with a stream of cold 

 water to remove corpuscles. Fairly uniform and compact strands of the 

 fibrin were selected , t and portions as nearly equal as possible were placed 

 in test tubes with 10 cc. of distilled water, plugged with cotton, and sterilized 

 for 20 minutes in an autoclave. Other portions were stained with I percent 

 Congo red and the color was fixed by immersion in boiling water. The 

 red color is liberated when the fibrin is digested. The colored fibrin was 

 also sterilized. 



Table 13. Fermi's Gelatin Test 



5 cc. Fermi's gelatin, 5 cc. H 2 0, 100 mg. pollen, 37 C. Degrees of liquefaction or 

 failure to solidify, after standing in ice water 10 minutes, indicated by signs. 



Kind of Pollen 



1 . Apple 



2. Corn 



3. Daisy 



4. Dandelion 



5. Dock 



6. Elm 



7. Goldenrod 



8. Lily, Easter 



9. Lily, tiger 



10. Pine, Austrian 



11. Pine, white 



12. Ragweed 



13- R ye 



14. Timothy 



15. Magnolia 



16. Maple, Norway 



Unheated Pollen 



24 Hrs. 



Hrs. 



Autoclaved Pollen 



24 Hrs. 



48 Hrs. 



+ 



+ 



+ 



+ 

 + + 



+ 



+ 

 + + 

 + + 



+ 



+ 

 + + + 

 + + 



+ 

 + + 



+ 



+ + 



+ 



+ 



+ 

 + + + 

 + + 

 + + 

 + + + 

 + + 

 + + + 

 + + 



+ + + + 

 + + 



+ 

 + + + 



+ 



2. Fermi's gelatin. The proportions used were those given by Dernby. 

 700 grams of gelatin were dissolved in 1,250 cc. of hot water over a water 

 bath, strained through cheese cloth, and 2 grams of finely pulverized thymol 

 were added. The solution was diluted to 2 liters and sterilized. Dernby 

 diluted further before using, but this was not found necessary with the 

 pollen extracts. When the gelatin was used it was melted over a bath and 



