PART I.] Observations on Boiled Solution of Meat. 33 



test tube was set aside for another fortnight, and was found to contain larger 

 animalculse than before, belonging to the Kolpoda family ; no cilia could be made 

 out, but a contractile vacuole was very evident. The various stages in the life 

 history of these animalcuise will be minutely described further on, in connection 

 with other observations. 



At the end of the third month cilia were easily demonstrable. The animal- 

 cule very closely corresponds to the Paramecium Kolpoda of authors. 



(c) A portion of the boiled solution of meat used at (b) was placed in another 

 test tube, filtered with a perforated cork, in which was introduced a piece of glass- 

 tubing bent a little more than at right angles; one end was dipped into the fluid in 

 the tube, and the other was drawn out to a very fine point, but not perfectly closed 

 up. This was devised with the intention of ascertaining whether expired air would 

 produce any alteration in the forms of life which might subsequent!}' become manifest 

 in the decoction, as a preliminary to future experiments on organisms developed in 

 crowded and empty rooms. With this view, the test tube was breathed into once 

 or twice daily for a fortnight, then set aside in order that a film might have 

 an opportunity of forming. 



At the end of three months the cork and glass-tubing were removed. A delicate 

 film had formed, which on being touched sank to the bottom of the tube. The fluid 

 was clear, free from smell, and presented no organisms when examined microscopically. 

 A portion of the subsided film was removed by means of a pipette. It consisted of 

 minute molecules and filaments held together by a slimy substance. Imbedded in 

 the midst of these were a great number of yellow globules-, microscopically not 

 distinguishable from globules of oil. The appearance presented by the field is 

 carefully delineated at Plate XVIII, Fig. Ixxii. They were unaffected by liquor 

 potassae, iodine, and dilute acids for some time ; eventually, however, more or less 

 granular contents became evident ; no organic connection could be seen to exist 

 between the globules and the filaments, and no animalcule of any family was present. 



A small portion of the film was placed upon a growing slide, and a drop 

 of the solution of grape-sugar and phosphate of ammonia added to it, so as 

 to ascertain whether they were spores of a fungus or the "still" condition of one of 

 the infusoria. 



The particular growing slide used was the one devised by Dr. Maddox, — by 

 far the best cell with which I am acquainted for purposes of this kind. A strip 

 of tinfoil is cut into two (J-sbaped pieces, one being larger than the other, so that 

 when the smaller is placed upside down f\, it will fit loosely inside the upright 

 portion of the other. These are stuck in this position on a glass slide with a 

 little varnish, over which a thin covering glass is so fixed that the only air 

 or foreign matter which can reach the preparation must pass up the " chimney " 

 thus formed between the inner margin of the larger strip of the tinfoil and the outer 

 one of the smaller, as will be readily seen by referring to Fig. Ixxv. 



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