Mabch 16, 1906.] 



SCIENCE. 



423 



green also. The green color is produced 

 in both light and darkness. 



The Traumatic Reactions of Living and 

 Extinct Araucarians: Professor E. C. 

 Jeffrey, Harvard University. 

 Among the Abietinese Abies and its allies, 

 although possessing normally no resin 

 canals in the secondary wood, form trau- 

 matic resin canals as the result of injury. 

 The presence of resin canals as a constant 

 and normal feature of the first woody ring 

 of the root in Abies, etc., as well as their 

 occasional occurrence in the first annual 

 ring of the vegetative and reproductive 

 branches of the stem, leads to the inference 

 that the traumatic resin canals of the 

 abietoid Abietineee are a reversionary fea- 

 ture. The examination of a considerable 

 number of species of the living aracaurian 

 genera Dammara (Agathis) and Araucaria 

 has resulted in the conclusion that the liv- 

 ing Araucarineffl do not produce traumatic 

 resin canals. The present author has been 

 able to extend this conclusion to certain ex- 

 tinct Araucarians from the Cretaceous beds 

 genera Dammara (Agathis) and Araucaria 

 oxyla of the Cretaceous beds of the eastern 

 United States, however, show a very differ- 

 ent wound reaction from that found in 

 Agathis and Araucaria, for they form 

 traumatic resin canals very abundantly as 

 a result of injury. These occur in the 

 usual tangential rows characteristic of 

 traumatic canals and contain mucilage as 

 well as resin, as is commonly the case in the 

 cortical resin-canals of the living Arau- 

 carineffi. The Araucarioxyla which react 

 in this way are characterized by the small 

 size of their tracheids and the complete 

 absence of the resin-containing elements, 

 which are found in the wood of living 

 Araucarinese. There is good reason to be- 

 lieve that these Araucarioxyla are the wood 

 of Brachyphyllum Brongniart, which thus 



takes its place among the Araucarinese and 

 in that most ancient group, which includes 

 Walcliia, Ullmannia, Pagiophyllum, etc. 

 Traumatic resin canals have been found in 

 araucariosylous material from the Raritan 

 formation of Staten Island, from Martha's 

 Vineyard and from the much older deposits 

 of the Potomac. The writer is of the 

 opinion that these facts will turn out to 

 be of considerable phylogenetic significance. 



Some Experiinents in the Control of 

 Color in Plants: Dr. Henry Kramer, 

 Philadelphia College of Pharmacy. 

 In a paper presented to this society a 

 year ago the author gave the results of 

 some morphological and chemical studies 

 on the color substances of plants. An ex- 

 amination of a large number of the un- 

 organized or cell-sap color substances 

 showed that they readily react with various 

 chemicals, a marked change in color being 

 produced in many instances. For example, 

 the majority of plant-color substances turn 

 green with calcium hydrate, deep red with 

 organic acids, rich purple with potassium 

 and aluminum sulphate, and blue with fer- 

 rous sulphate. While the color substances 

 in plants are considered to be in the nature 

 of metabolic products, still it is likely that 

 the various tints and shades are due to cer- 

 tain associated substances, as organic acids, 

 phosphates, calcium salts, etc. 



It has been repeatedly observed in the 

 study of certain ehromogenic bacteria that 

 the intensity of the pigment is dependent 

 in great measure upon the nutrient media 

 used. The addition of chemicals like mag- 

 nesium sulphate, potassium phosphate and 

 grape sugar, is found to be necessary for 

 the development of the pigment. Overton 

 found some years ago that by feeding cer- 

 tain plants with glucose there was an in- 

 crease in the red coloration of the leaves. 

 Katie has recently published some observa- 



