416 



SCIENCE 



[N. S. Vol. XXVI. No. 6G5 



round themselves off into little spheres or 

 -Stretch out into long bands, their cilia re- 

 main active for a week or more and a typical 

 cuticular border develops. Masses of cells 

 taken from, the myotomes differentiate into 

 muscle fibers showing fibrillse with typical 

 ■striations. When portions of myotomes are 

 left attached to a piece of the medullary cord, 

 the muscle fibers which develop will, after two 

 or three days, exhibit frequent contractions. 

 In pieces of nervous tissue numerous fibers are 

 formed, though owing to the fact that they are 

 developed largely within the mass of trans- 

 planted tissue itself, their mode of develop- 

 ment can not always be followed. However, 

 in a large number of cases fibers were observed 

 which left the mass of nerve tissue and ex- 

 tended out into the surrounding lymph clot. 



It has not yet been found possible to make 

 permanent specimens which show the isolated 

 nerve fibers completely intact. The structures 

 are so delicate that mere immersion in the 

 preserving fluid is sufficient to cause violent 

 tearing and this very frequently results in the 

 tearing away of the tissue in its entirety from 

 the clot. Nevertheless, sections have been cut 

 of some of the specimens and nerves have been 

 traced from the walls of the medullary tube, 

 but they were in all cases broken off short. 



In view of this difliculty an effort, which re- 

 sulted successfully, was made to obtain per- 

 manent specimens in a somewhat different 

 way. A piece of medullary cord about four or 

 five segments long was excised from an embryo 

 .and this was replaced by a cylindrical clot of 

 proper length and caliber, which was ob- 

 i;ained by allowing blood or lymph of an adult 

 •frog to clot in a capillary tube. No difficulty 

 was experienced in healing the clot into the 

 ■embryo in proper position. After two, three 

 or four days the specimens were preserved and 

 examined in serial sections. It was found that 

 the funicular fibers from the brain and an- 

 terior part of the cord, consisting of naked 

 axones without sheath cells, had grown for a 

 considerable distance into the clot. 



These and many other interesting observa- 

 tions described by the author show beyond 

 question that the nerve fiber develops by the 



outflowing of protoplasm from the central 

 cells. This protoplasm retains its amoeboid 

 activity at its distal end, the result being that 

 it is drawn out into a long thread which be- 

 comes the axis cylinder. No other cells or 

 living structures take part in this process. 

 The development of the nerve fiber is thus 

 brought about by means of one of the very 

 primitive properties of living protoplasm, 

 amoeboid movement, which, though probably 

 common to some extent to all the cells of the 

 embryo, is especially accentuated in the nerve 

 cells at this period of development. 



The Presence of AUantoin in the Urine of the 

 Dog During Starvation: Frank P. Under- 



HILL. 



During the progress of an investigation 

 upon intermediary metabolism, it became 

 necessary to subject the experimental animals 

 to periods of starvation lasting from ten days 

 to two weeks. From the urine of these dogs 

 allantoin separated spontaneously in pure 

 white crystals and the presence of this sub- 

 stance in the urine was constant. The pres- 

 ence of allantoin in the urine during starva- 

 tion has not been recorded hitherto. This 

 observation makes it probable that allantoin is 

 a constant constituent of the urine of the dog. 



Alhdloidal Compounds of Mucoids, Nucleo- 



proteins, and other Proteins: Walter H. 



Eddy and Willl\m J. Gies. 



In continuation of their studies of protein 

 compounds the authors have observed that 

 nucleoprotein, mucoid, caseinogen and alkali 

 albuminate form water-soluble products with 

 alkaloids. By intimately mixing samples of 

 the purified moist protein and the pure alka- 

 loid, especially with the latter in considerable 

 excess, soluble products are formed, which may 

 be precipitated by alcohol or alcohol-ether, 

 and which, after purification and drying, 

 readily dissolve in water. Such aqueous solu- 

 tions are neutral to litmus, and the proteins 

 may be readily precipitated from the solutions 

 by slightly acidifying them. 



The purification of such products as well as 

 their chemical and pharmacological study, is 

 under way. William J. Gies, 



Secretary 



