194 



SCIENCE. 



[Vol. VI., No. 135. 



Several speakers following Professor Bessey, com- 

 mended the sentiments of his paper, and deprecated 

 the undue attention given to systematic botany in 

 many cases, where the chief end of the study seems 

 to be to enable the student to find out the technical 

 name of the plant. 



A paper by Prof. T, J. Burrill of Illinois, upon 

 * An experiment in silk-culture,' came next upon the 

 programme. The experiment was but very partially 

 successful as regards the production of silk, the larger 

 part of the worms dying of a contagious disease at 

 about the time when they should have formed co- 

 coons. The investigation of this disease forined the 

 main subject of the paper. The disease was identi- 

 fied by the author, and by Professor Forbes, with the 

 Jiacherie of Pasteur, and was plainly not the disease 

 which he describes under the name pebrine. It also ap- 

 pears to be identical with a disease which has lately 

 proved very fatal to the larvae of the cabbage butterfly. 



The writer was not aware that any one had previ- 

 ously positively determined the existence of true 

 flacherie, or of pebrine in America; but, if the con- 

 clusions of his paper were correct, the former, at 

 least, has, in all probability, long existed here un- 

 recognized. 



In remarking upon the above papers. Prof. C. Y. 

 Riley claimed that both these diseases of the silk- 

 worm had been recognized by entomologists in this 

 country, though they had not been able to give the 

 disease that careful microscopical and bacteriological 

 study which Professors Burrill and Forbes had done. 

 He also stated his belief that the germs of flacherie 

 are omnipresent, and that the disease may be in- 

 duced at any time by unsanitary conditions. 



A paper followed by Major Henry E. Alvord of 

 New York, upon ' Telemetric aid to meteorological 

 records,' describing briefly an apparatus made by the 

 Telethermometer company of New- York city, by 

 which a continuous record of temperature can be 

 obtained at any reasonable distance from the place 

 of observation, and with very little trouble. The re- 

 sults of about six months' comparison of one of 

 these instruments, with thirteen daily readings of a 

 standard mercurial thermometer, showed a toler- 

 ably close agreement between the two. The tele- 

 thermometer was slightly tardy in its changes, and 

 usually failed markedly to reach the minimum daily 

 temperature, and frequently fell a little short of the 

 maximum. The author considered it — though by 

 no means perfect — to be the best aid yet found for 

 recording atmospheric temperatures in connection 

 with agricultural studies. 



The next paper was by Prof. H. P. Armsby of Wis- 

 consin, upon ' The creaming of milk by the Cooley 

 system.' It was chiefly statistical, giving the results of 

 some two hundred and fifty experiments in creaming 

 the milk of single cans by this system; and showing 

 that in eleven hours 90-99 per cent of the fat of the milk 

 was recovered in the cream, as against 75-80 per cent in 

 some recently reported German experiments in which 

 the temperature of the water surrounding the cans of 

 milk was much higher. The experiments furnished 

 also some hints as to further investigations upon the 



influence of small variations of temperature upon the 

 process, but no definite conclusions. 



A paper by Prof. G. C. Caldwell of New York, upon 

 ' The lactobutyrometer,' consisted chiefly of a review 

 of the tests of this instrument on record; but con- 

 tained also some experiments as to the cause of the 

 failure of the process in certain cases to extract even 

 approximately all the fat from milk, particularly that 

 from highly-fed cows. The author concludes that 

 his experiments are at least not inconsistent with 

 the belief that either an albuminous envelope, or some 

 sort of an accumulation of albuminoid matter about 

 the fat globules, gives rise to the difficulty. 



A brief report by Prof. W. J. Beal, upon the prog- 

 ress of experiments on the vitality of buried seeds, 

 and a short account by Prof. C. V. Riley of a new 

 remedy for locusts, which has been successfully used 

 in California, and the reading by title of a paper by 

 Prof. E. W. Hilgard " On some redeeming traits of 

 'alkali ' soils," closed the reading of papers. 



At the business meeting, the following officers were 

 elected for the ensuing year: President, Henry E. 

 Alvord; secretary and treasurer, B. D. Halsted; 

 executive committee, Henry E. Alvord, B. D. Hal- 

 sted, and E. M. Shelton. 



THE DEVELOPMENT OF THE EYE. 



In a recent paper before the Philadelphia academy, 

 Dr. Benjamin Sharp has endeavored to trace the de- 

 velopment of the highly complex vertebrate eye from 

 the simplest deposit of pigment in an epithelial cell. 

 The simplest organ of vision is found in the Lamelli- 

 branchiata; but these are not the primitive organs 

 of the group, the ancestral eyes being present in a 

 few forms for a short time during the free larval 

 stage. The most primitive adult eyes are found in 

 the common oyster, in which the free edge of the 

 mantle is lined with a number 

 of epithelial cells (fig. 1) having 

 a nucleus (n), a deposit of pig- 

 ment (p), a transparent cuticula 

 (c), with an undoubted power of 

 vision. The next step of ad- 

 vance is illustrated in the com- 

 mon Yenus, in which the eyes 

 are confined to the most exposed part 

 of the body, the so-called siphon. So 

 far there has been no protection to the 

 visual organs other than that afforded 

 by the shell; but in Yenus the fact 

 that there are pigment cells at the 

 base as well as on the extremities of 

 the tentacles indicates a change soon 

 o take place. This change is well 

 shown in the razor-shell Solen (fig. 2), 

 where all the eyes are arranged about 

 the base of the tentacles, and, fur- 

 thermore, are sunk into deep grooves. 

 The organ is also much more per- 

 fect. 



In the Gastropoda, from which the lamellibranchs 

 have probably degenerated, the visual organs take 



Fig. 1. — Visual cells 

 of Ostrea virginica. 

 c, cuticle; p, pig- 

 ment; n, nucleus. 



Fig. -2. — One 

 visual cell of 

 Solen vagina, 

 c, cuticle; p, 

 pigment; n, 

 nucleus. 



