Scientific Proceedings. 



(231) 61 



Sixteenth meeting. 1 



Rockefeller Institute for Medical Research. April 18, 1906. 

 President Flexner in the chair. 



35 (127). "On the digestion of gelatin": P. A. LEVENE and 

 W. A. BEATTY. 



A complete separation of all aminoacids arising on hydrolysis 

 of proteins was effected with the aid of phosphotungstic acid. On 

 hydrolysis of gelatin by means of strong hydrochloric acid, glyco- 

 col, alanin, leucin, aspartic and glutamic acids, phenylalanin, 

 prolin and oxyprolin, and a few substances of undefined nature, 

 were obtained. On tryptic digestion a substance of the composi- 

 tion C 7 H 10 N 2 O 2 was isolated. On further hydrolysis this sub- 

 stance yielded prolin and glycocol. The substance was evi- 

 dently prolinglycyl anhydrid. 



36 (128). 11 The reactions of amphioxus to light " : G. H. 

 PARKER. 



When strong light was thrown into a basin of sea-water con- 

 taining many amphioxus, the whole assembly swam about in wild 

 confusion. This has been taken to indicate that amphioxus is very 

 sensitive to light. But when 20 individuals were illuminated singly 

 only 1 2 responded. The wild confusion in the first experiment is 

 due quite as much to tactile stimulation as to light. When a 

 strong, well-circumscribed beam of light was thrown on the tail of 

 amphioxus the animal almost always reacted by a slight forward 

 spring. When the light was thrown on the middle of the body 

 there was usually no reaction, though sometimes a backward move- 

 ment. When the light was applied to the head end, there was 

 always a backward spring. This sensitiveness was not lost or im- 

 paired by cutting off the anterior end, including the so-called eye- 

 spot. When cut into halves amphioxus retained sensitiveness to 

 light in the anterior half, but not in the posterior half, though the 

 latter was normally reactive to stimulation from very weak acid. 

 This indicates that though amphioxus is without a brain proper, 

 the anterior portion of its medullary tube is related to the posterior 

 portion somewhat as the brain and cord are in the higher verte- 

 brates. The distribution of the sensitiveness of amphioxus to light 



1 Science, 1 906, xxiii, p. 846 ; American Afedicine, 1906, i (N. S. ), p. 152. 



