June 11, 1920] 



SCIENCE 



595 



The contents of the other two vials are of 

 much greater interest. In each case, the 

 material was taken from the stomach of a 

 duck collected at Bayou Labatre, Alabama. 

 One vial contains two small brown holo- 

 thurians, somewhat damaged but with the cal- 

 careous particles in the skin not at all cor- 

 roded or injured in any way. The condition 

 of these specimens leaves no doubt in my 

 mind that they were swallowed alive by the 

 duck and that they had been in the stomach 

 of the bird but a short time when the duck 

 was taken. These holothurians are unques- 

 tionably some species of Thyone, and are very 

 near, if not identical with, Thyone scahra 

 Verrill, of the southern "New England coast 

 But Thyone scahra is not known from south 

 of Delaware or from water less than ten 

 fathoms deep. No holothurians of any sort 

 are recorded from the Alabama coast. This 

 duck's stomach therefore reveals the interest- 

 ing fact that a species of Thyone, possibly 

 scahra but probably distinct, lives in shallow 

 water on the Alabama coast and serves as a 

 part of the diet for bottom-feeding ducks. 



The contents of the fourth vial confirms 

 this conclusion and reveals further the notable 

 fact that brittle-stars also serve as food for 

 ducks. The material in this case is in very 

 bad condition and is more or less digested, 

 but the calcareous particles in the fragments 

 of a holothurian indicate it is the same 

 Thyone as in the other vial, though it has 

 quite lost its pigmentation. Besides these 

 Thyone fragments there are numerous arm- 

 plates of a brittle-star. These are however, 

 beyond identification and one can not even 

 guess the genus, which they represent. The 

 brittle-star was however an individual of 

 moderate size and was certainly not the small 

 and well-nigh ubiquitous Amphipholis squa- 

 mata. No brittle-star is as yet recorded from 

 the Alabama coast. It is to be hoped that the 

 publication of the results of the collecting 

 done by these two ducks may lead to equally 

 effective efforts by some zoologist on the 

 Gulf Coast. 



Hubert Lyman Claek 



Museum of Compakative Zoologt, 

 Cambruige, Mass., 



THE AMERICAN PHILOSOPHICAL SO- 

 CIETY. II 



Morning Session — 10 o'clocTc 

 Akthuk a. Notes, Se.D., LL.D., VieeHpresident, 

 in the chair 

 The components and colloidal behavior of proto- 

 plasm: D. T. MacDougal, Ph.D., LL.D., director 

 of the Desert Laboratory, Carnegie Institution, 

 Tucson, Arizona, and H. A. Spoehr. The living 

 matter of plants is composed chiefly of mucilages 

 and albuminous compounds in varying proportions 

 mixed in the form of an emulsion or as a jelly. 

 The molecules of solid matter are aggregated into 

 groups which also include a number of molecules 

 of water. Growth consists of the absorption of 

 additional water to these groups, with more solid 

 material being added at the same time, the process 

 being termed hydration. The resultant increase 

 may be detected by determination of increased dry 

 weight, or measured- as increase in length, thick- 

 ness or volume. More exact studies in growth 

 have become possible by the establishment of the 

 fact that mlstures of 25 to 50 per cent, mucilage 

 and 50 to 75 per cent, albumin show the hydration 

 reactions of cell-masses of. plants. It is also found 

 that certain amino-compounds, such as histidine, 

 glyeocoll, alanin, and phenyl-alaniu which are 

 known to promote growth also increase the hydra- 

 tion of the iiocolloids as the above mixtures are 

 called. Following these empirical tests which have 

 defined the character and field of research upon 

 growth, measurements are now being made of the 

 action of various ions or substances upon the com- 

 ponents of protoplasm. Thus the strong metallic 

 bases, potassium, sodium and lithium, exert a lim- 

 iting action on hydration of carbohydrate (agar) 

 in hundredth normal solution according to their 

 position in the electromotive series, potassium be- 

 ing the strongest and reducing swelling most. 

 Eubidium, however, did not take its place at the 

 head of the list in the single series of tests made, 

 for reasons we are not able to describe. At dilute 

 concentrations (0.000, IN) all these bases promote 

 hydration, an effect also produced by amino-com- 

 pounds. The inclusion of substances in a liquefied 

 colloid, afterwards dried, produces a hydration effect 

 different from that which results from placing the 

 substance in the water in which the biocoUoid may 

 be placed. This fact has wide significance in the 

 physiological action of cell-masses. Eenewal or 

 replacement of hydrating solutions may result in 

 pulsations or rapid swellings followed Tjj slow 

 shrinkages or retractions. Gels s-imilar to those 

 entering into living matter may take on structure 

 by which small masses or sections may display 



