706 



of|ii!il to ^7.S^ jrrams carlioiiatr- of liuie, tin- slullsalono coiitainiiiji ^G.6 ^anis. TliP. 

 I'cdd coiisiinii'il an*I ilriiikiii^ water givtu tlioiii <oiitaiiiid <ak'iiim o<|iial tci 10.08 

 <;raiii8 cailionatc oj liim-. TJie oyster sLills taken !ty tluiii eoiitaiu«tl ISO.J'Jt ;rranis 

 carlxMiate ol" liuie. Of tbe carljoiiatc of lime eontaiiietl iu the e;:;;.s during the first 

 jieriod, lO.Sl <:;rams (over 84 jier eent), and of that in the e;igs during the second 

 IM-riod, 77. K) grams (<iverS(; jier cent), are unaccounted for. exceiit l>y the carbonate of 

 lime in the oyster shells, of which Uy.2 gi'ams were consumed during the first period 

 and l!tl.4 grams during the second. 



The dirterencc is so great that no other conclusion seems jiossihh' than that the 

 egg shells were constiiicted iiom material supplied in large part by the oyster shells. 



These hens lost in weight a total of 5 ounces during the lirst piriod an<l a total of 

 2 ounce s during the second, a ch;ingc in weight of little conseciucuce anil one that 

 might have occurred at any time within a few hours. 



Tlu' lot re('«'iviii,i: |i(»uii(l((l glas.'; did not ].\y as woll as tin* other lot, 

 and two ottln' lions bccanic sick, but ifcovcifd after a frw days. The 

 sickness is hdievcd to be due to excessive amount of jilass swallowed, 

 which amounted t<» .{l,."; per cent of the total water-free food when 



_iii\en <i(l lihUuni. -.[wd to iMJ.l ]ier rent when Ihe consnni])tion was lim 

 it<'(l. 



These hens gained iu weight during the lirst ]ieriod 11 oiniees and lost during the 

 seecuid jieriod [) ounci s. Altliougli fewer eggs were laid by this lot the shells were 

 ligliter, being iu the lirst jterind H.1'2 ]ier cent nf tlie total weight of the eggs and in 

 the second jieriod U.IX )ier cent, while the shells of eggs laid by tin- lot having 

 oyster shells formed !t.ti7 jier cent and 9.5 per cent of the total weight of tlieeggs. 



The egg shells contained !i2.4li per cent of carbonate of lime, and the ash of the 

 eggs, exclusive of shell. 4.!lt> ]ier cent of calcium, equal to 12.4 per cent of carlMinate. 

 Tile eggs for Ihe lirst jierind eont-Jiined l.Ol ]ter cent, and those of the second (>.^^ per 

 cent of ash. 



The amount of lime calculated as carbonate found iu the eggs exceeded that in tlie 

 food and ilriuking M ater by :!.!' grams for one period and nearly ;{ grams for the other. 

 Wiiiie the glass taken during one |ieriod contained lime, the ei|uivaleiit of ll(>.)iS 

 li ranis of earl ton ate. and during the other of ;^><.."><i grams, it does not a]i]iear jtrobable 

 tliat any of this was available as egg-shell material, for it existed in couibiuatiou 

 with various insoliilde silicates. Treatment of the linely-jiowtlered glass with the 

 ordinary acids failed to dissolve a trace of lime, and fusion with alk.iline carbon:ites 

 was necessary to its estimation. I'y.ttu examination of the excrement. t»f which 

 iluriug the lirst i»eri«»d over 72 jier cent of the air-dried substance consisted of frag- 

 ments of glass large enough to be easily removed by washing, a very few small 

 rounded fragments of limestone were found whi<h must havi' been swallowed by 

 the hens ]Mevious to their close conlinemeut and retained for from 10 to 20 days. 

 These small jiebbles of limestone had been subjected to conditions which are seen to 

 have made oyster shells available material. :inil it is probable that enough lime 

 was dissolved from them or from smaHer fragments, no a)i]ireciab|e portions of which 

 were left in the excrement, to have sn]>plicd the 3 or 4 grams of lime. • • • 



[In conclusion,] the feeding of oyster shells during the laying season, where they 

 can lie cheaply obl.iiiii d. is reeomnujnUd. One pound will cuutuin lime enough for 

 tbe sllells of about 7 do/en of eggs. 



Fine gravel containing limestone will jtroliably as well suiijily the delieiency of 

 lime existing in most foods, but the use of some shar]»er grit with it may be of 

 ad\ antage. 



Long or sharji sjiliuters of glass or dry bone sliould be avoided. For hens, tin- 

 size of jtart ides of grit had belter be larger than that of a kernel of wheat and ebould 

 be smaller than that of a kernel of corn. 



