NOTES. 



5ii 



arate images presented to the brain, one 

 blurred and indistinct, even for faces a 

 yard distant, and the other clearly defined 

 for objects at ordinary distances. " How is 

 it," he asks, " that my brain or mind rejects 

 the blurred image, and chooses the distinct 

 one ? .... If I get a particle of dust in 

 the good eye, or close it, I immediately see 

 the blurred image. . . . This blurred image 

 always appears at a higher level than the 

 other. Things appear as a rule," he adds, 

 " much flatter to me than to people who 

 enjoy binocular vision. I know this be- 

 cause I have a pair of spectacles so arranged 

 as to equalize my sight. When I put them 

 on, objects like trees put on a delightful 

 fullness and roundness to which I am usu- 

 ally quite a stranger. I may add that two 

 of my brothers have a similar defect of 

 vision." 



The Cactns as a Lava-Breaker. A cita- 

 tion, in the bulletin of the Torrey Botanical 

 Club, from Dr. Peters, the famous asteroid- 

 hunter, gives an interesting fact in relation 

 to the doctor's earlier days, when he ate 

 prickly pears, or the fruit of the Indian-fig 

 cactus, on the sides of Mount Etna. He de- 

 scribes the lava-beds as covered with im- 

 penetrable patches of Opuntia jicus Lidica^ 

 the Indian fig-cactus. These patches are 

 the result of economic planting, with the in- 

 tention of producing soil on the lava-beds. 

 The Sicilian throws down a handful of soil, 

 then drops upon this a bit of the cactus, 

 which immediately roots. The effect of this 

 cactus-growth is to facilitate the weather- 

 ing of the rock, and thus make soil. The 

 next step, after clearing off the cactus, is to 

 plant fig-trees. In this way the lava-beds 

 of Mount Etna are transformed into fruit- 

 ful gardens. 



A New Septic Organism. Mr. Dal- 



linger lately gave, before the London Royal 

 Society, an interesting account of the life- 

 history of a peculiar microscopic organism 

 discovered by him in certain decomposing 

 fluids. This organism never exceeds the 

 4^00 of an inch in long diameter ; in shape 

 it is oval ; at its anterior extremity it has a 

 head-like protrusion bearing a delisate fla- 

 gellum. From the sides of the shorter or 

 front segment of the oval project two long 

 flagella, and these, as a rule, trail behind, 



one on each side. It swims rapidly, but has 

 also the capacity of anchoring both of its 

 lateral flagella to the floor of the microscope- 

 stage, or to a decomposing mass in the drop 

 of liquid in which it is examined under the 

 microscope. By steadily observing it in the 

 free-swimming condition, it may be seen to 

 undergo self-division, the division beginning 

 in the front flagellum, and proceeding until, 

 by longitudinal fissure, a new lateral flagel- 

 lum is made for each half. There are now 

 two perfect organisms. The author con- 

 fined his attention for some time continu- 

 ously to one of the segmental portions, and 

 succeeded in tracing the process to its ulti- 

 mate results. Having so observed a num- 

 ber of the self-dividing organisms, he found 

 that in the majority of cases, when the pro- 

 cess of fissure ceased, there was simultane- 

 ous exhaustion of vital action, and death ; 

 but in a certain proportion of cases, in which 

 fissure was not so long continued, there was 

 a change to the amoeboid condition, the lat- 

 eral flagella being absorbed, and the body 

 becoming oval with anterior flagellum only. 

 It now swims easily, but only in a straight 

 line. It soon comes in contact with a col- 

 ony of the organism in the perfectly flagel- 

 late condition, attaches itself to one of them, 

 which soon unanchors, and both swim away. 

 In course of time their movements become 

 sluggish ; the sarcode of their bodies is pal- 

 pably blending, they become quite still, ex- 

 cept for amoeboid movements, and then be- 

 come one oval mass. After three or four 

 hours this pours out minute specks, which 

 appear to develop into the adult form and 

 size. The temperature of 142 Fahr. is fatal 

 to the perfect organism ; the " speck," germ, 

 or spore, can bear with impunity a temper- 

 ature of 250 Fahr. 



NOTES. 



The schooner Eothen, carrying the ex- 

 pedition to search for the relics of Sir John 

 Franklin's party, sailed from New York on 

 Wednesday, June 19th, under the command 

 of Captain Thomas F. Barry, whose discov- 

 ery of spoons bearing Sir John's crest, in 

 the hands of an Esquimaux tribe, was the oc- 

 casion of fitting out this expedition. Lieu- 

 tenant Schwatka, Third U. S. Cavalry, will 

 command the search-party, and will have 

 for guide and interpreter Joseph Ebarbing, 

 "Esquimaux Joe" of Polaris fame. The 



