6 



Scientific Proceedings. 



family Sciuridse may suggest an intermediate stage in the process 

 of evolution between the latter group and those higher mammals 

 in which the fibers radiate to all parts of the retina from a circular 

 optic disc. However, an extended investigation is necessary be- 

 fore any conclusion can be arrived at with regard to the possible 

 taxonomic value of this character. 



Experiments to trace the fibers of the optic tract are now in 

 progress. As the optic nerve is spread out near the eyeball, it is a 

 simple operation to cut either the inner or outer half for a study of 

 the degeneration of its fibers. 



So far I am not in a position to offer any opinion regarding 

 the physiological significance of this peculiarity. 



Note. — In the case of the squirrel and European marmot this 

 peculiarity in the optic nerve is mentioned in Cuvier's " Lecons 

 d'Anatomie Comparee," Tome 3B, p. 430. 



4 (613) 



Biological and toxicological studies upon Penicillium 



puberulum Bainier. 



By C. L. ALSBERG and 0. F. BLACK. 



[From the Bureau of Plant Industry, Washington, D. C] 



This species when grown upon Raulin's solution, in pure cul- 

 ture, produces a new organic acid which has been termed penicillic 

 acid. This acid gives a brownish-red solution when treated with 

 a dilute solution of ferric-chloride. With ammonia it gives a deep 

 red color. From the analyses, molecular weight determinations 

 and other data, it seems probable that this acid belongs to the 

 same general class of compounds as are found in lichens, and 

 termed lichen acids. Like them, it is slightly bitter and irritating. 

 Pharmacologically, it is moderately toxic, having an antiseptic 

 action and being a protoplasmic poison. It is not astonishing to 

 find substances of this class in fungi, since lichens are symbiotic 

 forms, composed of fungi and algae. The finding of this type 

 of substances in the pure culture of a fungus makes it probable 

 that in lichens, lichen acids are the product of the fungus meta- 

 bolism, and not of that of the algae. 



