66 



SCIENCE. 



[N. S. Vol. XII. No. 289. 



the surface. Four cells are thus formed 

 beneath the blastoderm, and they are ap- 

 parently added to the mesoblast, for in the 

 next stage their derivatives can not be dis- 

 tinguished from the rest of the mesoblast. 

 The entire mesoblast then originates from 

 one cell which is separated from the ento- 

 blast in the fourth cleavage (16-cell stage), 

 and from four other cells which are derived 

 from the ectoblast in the sixth cleavage 

 forming the 62-cell stage. The lineage of 

 these four ' secondary ' mesoblasts has been 

 traced back to the first and second ecto- 

 meres. 



The course of the cleavage as sketched 

 above has been determined to be quite con- 

 stant. Cells of definite origin in the early 

 cleavage stages are the ancestors of cells 

 which occupy particular positions in later 

 stages. Following Conklin's terminology 

 ('97), the cleavage may be characterized 

 as ' determinate.' This conclusion is com- 

 pletely opposed to the results of the earlier 

 investigators of Cirripede development. 



Gastrulation is of the epibolic type, and 

 is the result of the extension of the ecto- 

 blastic blastoderm over the entoblastieyolk- 

 macromere. The blastoderm usually closes 

 over the blastopore during the sixth cleav- 

 age (62 cells). The blastopore is identified 

 as marking the ventral and posterior of the 

 future embryo. 



In the general features of the late develop- 

 ment of the embryo the results of this in- 

 vestigation confirm those of some earlier 

 workers. 



A paper with figures in support of all 

 the above conclusions has been prepared, 

 and is now awaiting publication. 



Maurice A. Bigblow. 



Teachers College, 

 Columbia Univeksity. 



EBNST HAETIG. 

 Ernst Hartig, ' der Geheime Eegier- 

 ungsrat Professor Dr. Hartig ' of the ' kgl. 



Sachsische TechnischeHochschule,'at Dres- 

 den, died April 23rd. He was born, Jan. 

 20, 1836, studied at the Dresden Polytech- 

 nikum, finding in the late Geheimrat Pro- 

 fessor Dr. A Hulsse an inspiring teacher 

 and a warm friend through whose encour- 

 agement and aid he was induced promptly 

 to take up a line of study and work which 

 gave him, ultimately, large opportunities 

 and great reputation. He became, in 1862, 

 the assistant for mechanical technology and 

 was promoted to his professorship in 1865. 

 In 1890 he became the director of the Tech- 

 nical High school. He was active in the or- 

 ganization of the various technical depart- 

 ments and the laboratories of engineering 

 research and made himself an authority 

 relative to the materials of engineering and 

 in all departments of textile work. He 

 published some important papers. 



His ' Untersuchen uber die Heizkraft der 

 Steinkohlen Sachsens ' came out as early 

 as 1860 ; from 1864 to 1869 he was engaged 

 in the pursuit of a number of researches 

 and published the results of an experimen- 

 tal investigation of the power required in 

 the operation of spinning and weaving ma- 

 chinery. In 1873 he brought out his work 

 of similar character on the machine-tools 

 and in 1876 that on the machinery of the 

 combed wool manufacture. At the desire 

 of its author, then surrendering his hold 

 upon his long-sustained work in that direc- 

 tion, Hartig undertook the preparation and 

 admirably completed the issue of the fifth 

 edition of Karmarsch's ' Handbuch der 

 mechanischen Technologic ' for his old 

 friend and teacher and assumed thenceforth 

 the position of a leading authority in that 

 branch. From 1877 he had much to do 

 with the formulation and systematization 

 of the patent laws and patent systems of 

 the kingdom and of the empire, accomplish- 

 ing much for the inventor, and for the 

 courts as well. He was an admirer of the 

 United States system and recognized its 



