HARDWICKE'S SCIENCE-GOSSIP. 



135 



be uneasiness at the constraint caused by tlie 

 obsolescent cuticle, and ar desire for liberation from 

 it ; thus causing the reptile toinake an effort to that 

 end. The tadpole of the Smooth Newt reared by 

 myself last year, when leaving the water on the 

 assumption of the adult form, was shedding its 

 skin: it was then, as described by Mr. Bell, 

 " coming off in shreds." Its food had been such as 

 was obtainable in a small aquarium stocked with 

 aquatic plants. 



It is very probably due to an inadequate supply 

 of aliment that the young Newt in the aquarium 

 does not duly attain the adult size. Of this I am 

 satisfied, partly by the great disparity in size of 

 those tadpoles reared by myself last year, but 

 chiefly by a number of frog'^tadpoles which I had 

 hatched from spawn in my aquarium two years ago. 

 Erom nearly one hundred of those tadpoles 1 

 selected one, putting it in a vessel by itself for 

 closer inspection; the others were kept in a fair- 

 sized aquarium well stocked with plants. Thirteeu 

 days after, tlie solitary individual was one-fourth 

 larger than its fellows, which were, however, as 

 mature, so far as the absorption of the branchiae 

 and outward appearance were concerned. Eleven 

 days later it was one-half larger. A few days 

 subsequent, however, a quantity of aquatic plants, 

 taken from a swamp, being put into the aquarium, 

 and allowed to float on the surface of the water, 

 supplied them with abundance of aliment, and 

 henceforth they throve amain, most of them being 

 afterwards developed iato the frog state. 



Last year I again kept the Smooth Newt (a male 

 and female) for a time, and had the ova deposited, 

 not in the aquarium, but in a large glass jar, into 

 which the Newts were put on their receipt, along 

 with some Callitriche verna, brought with them, 

 and remaining unplanted. Upoa the leaves of 

 those plants were the eggs deposited ; some, as on 

 former occasions, in a folded leaf, some on under 

 side of leaves, and some between two leaves : these 

 two latter positions were probably owing, partly at 

 least, to the Callitriche being unplanted, and con- 

 sequently unstable. The Newts were got on June 

 15th, and three days later the first t^g was dis- 

 covered. More were laid the following day, and up 

 •to July 1st others were deposited. On tlie 21st of 

 June, in the afternoon, I removed the female Newt 

 into another vessel, in which were growing a few 

 plants of water- thyme. On the following morning 

 three eggs were discovered deposited near the top 

 of one of the plants in close proximity ; two in fact 

 were touching. Other eggs were afterwards laid, 

 but always singly, and on separate leaves. 



The eggs of the Smooth Newt are not, as stated 

 in my first paper, spherical, but oval. This was 

 readily seen in those eggs laid on the surface of the 

 leaves. On my first acquaintance with the eggs of 

 this species, on June 17tb, 187J, they were greatly 



advanced, and it was not until later that the folded 

 leaves in which they were deposited were sufTiciently 

 reopened by the maturing tadpole to admit of an 

 opinion being formed as to their shape. They were 

 then as represented [by the figures in that paper 

 (page 12S, last volume), the form undoubtedly 

 being determined by the body of the inclosed tad- 

 pole pressing against the aides of its envelope, com- 

 bined with the position of the egg on the leaf. 



The ova of this Newt was kept in a high tem- 

 perature, and its development was rapid. In from 

 ten to twelve days from its being deposited, the 

 tadpoles were hatched. The first was hatched on 

 June 28th, the last on July 11th. Many were the 

 sizes of the tadpoles, but one far exceeded its 

 fellows. This one was on July 25th about three- 

 fourths of an inch long, and possessed of hind legs. 

 On August 23rd its branchiae and tail-fin were 

 degenerating ; on the 25th, very observably so. 

 On the 2Sth it was out of the water upon a piece 

 of wood placed for serving that purpose ; its 

 branchiae were then nearly gone, and consisting of 

 three short points onl)-, and it was shedding its 

 skin, which hung upon it in shreds. It would now 

 be about one inch in length. On the following 

 morning it had disappeared, as had ere this its 

 elders. 



Newcastle-upon-Tyne, C. Robson. 



MICROSCOPY. 



Mounting with Balsam. — Your correspondent 

 E. Kitton is, I think, quite wrong in saying 

 the most important condition in mounting with 

 balsam is to keep the balsam free from chloroform. 

 Until I began to use chloroform very freely in the 

 different processes of mounting with balsam, I 

 could make vei'y little progress. Mr. Kitton's plan 

 I found very troublesome, and to result in many 

 failures. My own plan is to mix chloroform with 

 the balsam until it is sufficiently fluid to drop 

 nicely from the neck of an ounce vial. I prepare 

 the objects iu the usual way, soak them in turpen- 

 tine from a few minutes to several weeks, according 

 to the nature of the object, then place them on. the 

 slide, di'op the balsam on, cover with small round 

 glass, and set aside for some days ; by the end of 

 this time, which varies according to the nature of 

 the object, all the air-bubbles will have made their 

 way from under the glass (unless actually inclosed 

 in the substance of the object, which indicates 

 either too short time in the turpentine, or, in some 

 cases, the absolute need for the use of an air-pump). 

 The slides can be left in this state until these are 

 sufficient to bake, which I manage in the following 

 way : — I have a tin or copper box 12 inches square, 

 by 2^ inches deep, flat on the top : this 

 holds three dozen slides. I fill the box with water. 



