138 



NATURE 



[Dec. 14, 1876 



shown (I am not aware that it can) that he had definitely corre- 

 lated them with (Lower) Cambrian beds. T. G. BoNNEY 

 St. John's College, Cambridge, December 11 



Self-Fertilisation in Flowers 



Dr. MiJLLER (Nature, vol. xiv. p. 571) and Prof. Asa Gray 

 (vol. XV. p. 24) reflect on your abstract of my verbal remarks 

 (vol. xiv. p. 475) on Browallia in a way not [particularly com- 

 plimentary to me. Prof. Gray admits having read the full 

 report, and yet fails to notice that " February 8," is there given 

 as the date of my remarks. Had he not overlooked this, he 

 would not have wondered that I did not see " Hymenoptera and 

 Lepidoptera of various sorts " visiting them. As reported in the 

 Proceedings of the Society, I exhibited fresh specimens in fruit 

 at the meeting of that date, which is about mid-winter with us, 

 when these insects are at rest. The plants were of course grown 

 under glass, and when I say " Browallia is not visited by insects, 

 yet seeds abundantly," I am referring naturally to the experience 

 I am describing. If one be justified in taking an unguarded ex- 

 pression, or even a whole sentence, without any regard to the 

 subject matter of its connection, we might have as many 

 "theories" in science as there are sects in religion, all founded 

 on isolated *' texts " in Scripture. It is remarkable that in a 

 paper in which Prof. Gray is commenting on hasty observations, 

 in another he should have overlooked a fact like this. I do not 

 say Browallia is never visited by insects, but I do say that they 

 do not visit them ujider such circumstances as I ivas describing. 



Of ih.tfaci there is no doubt, of the interpretation there may 

 be many opinions ; and no one respects an opinion by Prof. Gray, 

 when he carefully considers it, more highly than I. Yet I 

 would respectfully submit, that even though an insect were as 

 careful to avoid the " brush " which almost closes the throat, 

 though it were able to be as careful in finding the chink as Dr. 

 Gray was in his manipulations with the hog's bristle, the obstruc- 

 tion of the mouth in the way it is cannot surely be claimed as 

 an arrangement in favour of cross-fertilisation. 



Dr. Miiller seems to believe that I do not know that " many 

 flowers have recourse to self- fertilisation when not visited by 

 insects. " If he will examine the Proceedings of the Am. Associa- 

 tion for 1875, p. 247, he will find that I have given him the 

 credit of the observation, and the fact itself such consideration I 

 thought it in justice entitled to. The impression which Dr. 

 Midler's expression warrants, that he has not had the opportu- 

 nity of reading the numerous observations I have placed on 

 record during the last few years, in relation to this and kindred 

 topics, fully excuses him in my mind for his sharp comments. 



Thomas Meeham 

 Germantown, Philadelphia, Nov. 21 



On Supersaturated Solutions 



In a paper communicated to the Royal Society last May I 

 described some experiments to show that the open air and the 

 air of ordinary rooms do not generally contain crystals of the 

 various salts which form supersaturated solutions. It has been 

 remarked to me that I did not give the strength of the solutions, 

 so that doubt might arise as to whether the results would hold 

 good for very strong solutions : — The following experiments set 

 that question at rest. I made a very strong solution of sodium 

 sulphate which threw down abundance of anhydrous salt on 

 boiling. When cold a good half inch of anhydrous salt re- 

 mained at the bottom of the test-tube. Took this into my 

 garden, which is near Bristol. Took up some of the solution in 

 a clean pipette and put drops on the leaves of peonies, which 

 were very dusty, on geraniums, on moss, on the stone coping of 

 Bath oolite, and on the painted woodwork of the railings and 

 garden door. Not a single drop crystallised. Made a drop set 

 quite solid by dropping in earth with the fingers. N.B. — I had 

 been at work with the salt for some time and crystals were pro- 

 bably adhering to my finger. Earth not touched inactive. The 

 drops sank into the moss slowly, remaining quite liquid. Those 

 on the stone were soon absorbed and dried up on the surface ; 

 fresh drops put on these remained liquid. Smeared a drop re- 

 peatedly with the finger which had been cleansed ; inactive, as 

 fresh drops remained liquid on it. Drop on flower-pot, inactive, 

 smeared with finger ; when dry inactive to fresh drops. These 

 and other drops on the flower-pot slowly formed a film of 7-atom 

 salt. Stirred the solution with a dry twig picked off" the ground, 

 inactive. The drops on the leaves all slowly evaporated, giving 

 the 7-atom salt. Finally, made some of the drops and the original 



solution crystallise, to prove that they were really supersaturated. 

 These experiments were made both in sun and shade. Weather 

 dry. The test-tube was left open the whole time. 



On another occasion I took a flask of sodium sulphate contain- 

 ing a large quantity of the 7-atom salt into the garden in the 

 evening. Put drops on a flower-pot ; one only crystallised. Put 

 a lump of dry earth into one drop, and added more solution ; 

 did not crystallise. Made a little mud pie by breaking this up 

 with the pipette, inactive ; pipette repeatedly inactive in the 

 solution after touching this. Brought a crystal to the earth; 

 crystallised at once all through the mass. 



Clifton College J. G. Grknfell 



KARL ERNST VON BAER 



SCIENCE has sustained a great loss by the death of 

 Dr. Karl Ernst von Baer, the eminent biologist ; he 

 died at Dorpat on November 29, in his eighty-fifth year. 

 Von Baer was born in Esthonia on February 29, 1792, 

 and while yet at the gymnasium became an earnest student 

 of botany. He studied medicine at Dorpat in 1810-14, 

 whence he proceeded to Vienna for the study of clinical 

 medicine, to Wiirzburg, where he gave special attention 

 to comparative anatomy, and to Berlin, where he studied 

 magnetism, electricity, crystallography, and geology. In 

 1 81 7 he went to Konigsberg as prosector to Prof. 

 Burdach, and two years later he became professor of 

 zoology at the same university. In 1826 he succeeded 

 Burdach in the chair of anatomy, accepted an invitation 

 in 1829 from the St. Petersburg Academy, but returned to 

 Konigsberg the following year. A few years ..later, in 

 1834 he was again invited to St. Petersburg, where he 

 became one of the most active members not only of the 

 Academy, but also of the Geographical and Economical 

 Societies. Von Baer's writings, marked by philosophic 

 depth, are, on account of their orderly and clear exposi- 

 tion, as attractive as they are generally intelligible. The 

 subject of the origin and development of organic bodies, 

 which had special attractions for him, he did much to 

 clear up. The foundation of his eminence he laid in 

 Konigsberg, where he published in 1827 his " Briefe iiber 

 die Enstehung des Eies," which was soon followed by the 

 important works " Entwickelungsgeschichte der Thiere," 

 and " Geschichte der Entwickelung der Fische." These 

 works, which are yet of great value, have earned for their 

 author the title of Father of Comparative Embryology. 



In the summer of 1837 von Baer made a journey of 

 exploration from Archangel to Novaya Zemlya, and his 

 report is still one of the most valuable sources of informa- 

 tion upon that island. In 1851 his attention was attracted 

 to the immense Russian fisheries and the irrational 

 methods used. During 1851-6 he investigated the fisheries 

 of Lake Peipus, the Gulf of Finland, and the Caspian 

 Sea, publishing the results of his investigations in a great 

 work in 1859. The name of Baer is connected with more 

 than one improvement in the fisheries, and some important 

 additions were made to the trade, thanks to his efforts. 

 His remarkable work, " Kaspische Studien," has had no 

 rival. It would be impossible to enumerate the various 

 subjects upon which he has thrown clear light in his 

 writings. The laws of excavation of river-beds, the navi- 

 gability of the Arctic seas, the steppes and forests of 

 Southern Russia, the Glacial period, the Siberian mam- 

 moths, the potato disease, were at various times treated 

 by him, and in each department von Baer opened out 

 new and extensive fields of inquiry. His acquire- 

 ments in zoology, comparative anatomy, embryology, 

 physiology, and anthropology are well known ; more- 

 over ethnography, the early history of mankind, archseo- 

 logy, and the science of language will count him 

 among their most eminent students. In his later years, 

 besides various anthropological papers, he published 

 an autobiography (which appeared soon after the 

 fiftieth anniversary— 1864— of his scientific career), hisi 

 " Reden," and " Kleine Aufsatze vermischten Inhalts " 



