206 



SCIENCE. 



[Vol. XXII. No. 558 



To test this matter in another way, I cajjtured a number 

 of specimens and with finely pointed scissors cut the 

 heart or dorsal vessel, at the middle of the thorax. These 

 insects lived nearly twenty-four hours, proving that the 

 circulation of blood is not dependent entirely upon the 

 heart, and, in fact, these insects lived as long as others 

 which were not mutilated at all, and were kept in the 

 same dish merely as a check. I could not find that these 

 insects differed in their actions in any way from those 

 that were perfectly normal. Another set of specimens 

 was treated by cutting not only through the heart, but 

 also through the oesophagus where it passed through the 

 prothorax, and thus the alimentary canal was severed. 

 Specimens so treated died somewhat sooner than did 

 the previous lot, although they also lived nearly twelve 

 hours. It was also noticed of these insects that the tongue 

 or proboscis was frequently extended and retracted as 

 in the case of those insects in which the abdomen was re- 

 moved. Another set of specimens was treated by cutting 

 the nervous cord in the thorax just behind the posterior 

 legs. This resulted in the paralysis of the hind legs, but 

 did not appear to affect either the fore and middle legs 

 or the wings. Where the cord was cut between the 

 middle and hind legs, exactly the same result was ob- 

 tained. Cutting the cord between the fore and middle 

 legs, close to the middle legs, however, resulted in the 

 paralysis of everything behind the fore legs, and of the 

 wings as well; although the insect lived for more than six 

 hours afterward, both the head and its appendages and the 

 fore legs responding readily to stimulation. As a result 

 of this crude series of experiments, it would seem that 

 the vital point, or, better, the controlling nerve centre in 

 flies, is located in that large ganglion situated in the pro- 

 thorax, just above the fore legs, and that so long as this 

 remains intact, the insect retains power of motion and 

 evidences active life. Severing or piercing this ganglion, 

 killed the insest at once. 



preventing this difficulty, and might be useful to students 

 who are collecting autumn flowers. 



A small square or disk is cut from blotting paper and 

 a hole is cut in its centre, a little larger than the head of 

 the flower. If, in pressing, this disk be put over the 

 flower, allowing the head to come up through the hole in 

 the centre, the rays can be pressed out flat. The thick- 

 ness of the disk should vary accordingly as the head is 

 thick or thin. Eichaed H. Eigh. 



Beverly, Mass., Sept. 25, 1893. 



LETTEES TO THE EDITOE. 



^♦^.Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as a proof of good faith. 



On request in advance, one hundred copies of the number con- 

 taining his communication will be furnished free to any corres- 

 pondent. 



The editor will be glad to publish any queries consonant with 

 the character of the iournal. 



Herbarium Specimens. 



In preparing specimens of the Composite family for the 

 herbarium, it is difiicult to press the flower so that the 



Minnesota Mounds. 



I BEAD with considerable surprise Mr. Schneider's arti- 

 cle entitled "Notes on Some Minnesota Mounds" in 

 Science of Sept. 1, and I at once felt it to be my painful 

 duty to correct some gross misrepresentations. I hap- 

 pened to be working in the same party with Mr. 

 Schneider when he made the valuable discoveries which 

 he describes and therefore am in a position to criticize his 

 statements. 



It is true that we found a number of Indian burial- 

 grounds in the vicinity of Mille Lacs. Most of these were 

 still in use, or had been so until quite recently. In two 

 which I assisted in opening we found some decidedly 

 modern relics, e. g., a U. S. ten cent piece used as a ban- 

 gle, a glass butter-dish, a rubber comb and a jack-knife 

 such as any Yankee boy might carry. These graves were 

 arranged in rows and were usually covered with super- 

 structures of wood, which might be compared to dog- 

 kennels. We found a few graves rather older than the 

 above, and which were covered with low mounds of 

 earth, but even here there were traces of wooden stakes, 

 which gave evidence of their recent origin. As to the 

 mound at Lake Warren, which Mi-. Schneider dug into, I 

 confess that I was not present when it was opened. I 

 have, however, seen the "relics" which were collected 

 from it — in fact I am in a position to see them whenever 

 I wish. Without stoj)ping to question whether the age, 

 sex and stature of the individuals could be accurately de- 

 termined from the very fragmentary skeletons which he 

 found, I would say that the bones are nearly as well pre- 

 served as some which we found in one of the covered 

 graves above described and which I know to have not 

 been buried more than twenty-five years. It is hardly 

 necessary to point out the absurdity of supposing that a 

 hole in which the "roughness of the sides" was still ap- 

 parent could have been filled for several hundred years. 



The specimens of pottery which he describes are mere- 

 ly fragments of baked clay utensils of the roughest sort, 

 just such as all the American Indians manufactured be- 

 fore they obtained iron kettles from the whites. 



In fact there is not the least evidence that any of these 

 bones or relics are of any great age or that they belong 

 to any race older than the Indians which inhabit this dis- 

 trict at present. They are of no more value to the archsB- 

 ologist than bones dug from the nearest cemetery. 



Fbancis B. Sdmnek. 



University of iVIinnesota, Minneapolis, Minn., Sept. 23, 1893. 



rays will not wilter, owing to the fact that the head keeps 

 the paper from pressing upon the rays. The following 

 device has been used by the writer with much success in 



Origin of Gold. 

 I WOULD like to draw attention to a somewhat fallacious 

 deduction which appeared in an interesting little article, 

 " The Origin of Grold," in your issue of Sept. 1st. The 

 author mentions the remarkable fact that, in a part of 

 Southern India, quartz-veins, though traversing both 

 gneiss and belts of rocks, which have been termed the 

 Dharwar, are gold-bearing in the Dharwar only, and are 

 never productive in the gneiss. Mr. Lake then argues: 

 " It is clear, therefore, that the gold cannot have been in- 

 troduced into the reefs from below, for in that case there 

 would be no difference in that respect between the reefs 

 in the gneiss and the reefs in the Dh^f war." 



