THE LUNGS. 179 



II, 2, p. 323). In the new-born child the secondary lobules 

 measure 2 — 3 — 4s" ; the alveoli, before they are filled with 

 air 0-03'", and after the first inspiration 0*03 — 004 — O06"' • 

 the latter at this time appear to exist in the same number 

 as in the adult, the further increase of the lungs proceeding 

 only from the expansion of all its parts. 



[The investigation of the lungs presents no real difficulty, 

 except in one point; that is, with respect to the relation 

 of the pulmonary cells to the terminations of the bronchia, 

 but here the difficulties are very considerable. In recent pre- 

 parations it is obvious that the air-cells communicate in many 

 ways, and in any case, that they are not merely terminal on 

 the extremities of the bronchia. If it be desired to investigate 

 the whole subject, inflated and dried lungs (it is better in an 

 inflated lung to tie off an end and dry it by itself), or corroded 

 preparations, or lungs injected with uncoloured substances 

 (wax and resin) are most suitable, and with such, a definite 

 result will be obtained, after a series of observations. 



Before the injection of the bronchia is proceeded with, the 

 air must be exhausted in the air-pump, for which purpose, also, 

 though less conveniently, a well-fitted syringe may be employed. 

 The injection of the blood-vessels is readily effected and the 

 preparations should be kept wet; sometimes, when injected 

 with opaque material, sometimes, following the processes of 

 Schroder and Harting, with transparent substances (Prussian 

 blue, &c), dried preparations are to be preferred. The air- 

 cells and bronchia, the larynx and trachea, are readily exa- 

 mined. The epithelium of the air-cells is obtained in large 

 quantity in every section through the lung, as well as ciliated 

 cells. If it be wished to study the alveoli, the air must pre- 

 viously be carefully removed. These are best displayed in 

 Man, in whom, also, all the other parts, such as cartilage, elastic 

 elements, muscles, and glands, are easily obtainable.] 



Literature. — M. Malpighi, 'De pulmonibus epistolae II ad 

 Borellum.' Bonon. 1661; F. D. Reisseisen, * Ueber den Bau 

 der Lungen, eine gekronte Preisschrift/ Berlin, 1822 ; J. Moles- 

 chott, ( De Malpighianis pulmonum vesiculis/ Heidi. 1845, Diss, 

 and, ' Ueber die letzten Endigungen der feinsten Bronchien/ in 

 the Hollandischen Beitragen, I, p. 7 ; Rossignol, ' Recherches 



