326 BLOTTING PAPER MODELS [ CH. X 



and sectioned being used as a guide by which the correct form of the pile of 

 sections can be tested. Finally the whole is welded into one by the use of 

 hot wax or a hot instrument. Models which illustrate complex internal struc- 

 tures are difficult to prepare, but numerous devices will occur to the worker, as 

 the representation of blood vessels and nerves by strings or wires. A large 

 model will need urach support which can be given by wire gauze, wires, pins 

 or paper according to the special needs. 



A practical method for wax modeling was first published by G. Born, Arch, 

 f. Mikr. Anat., Bd. xxii, 1883, p. 584. The most detailed statements of im- 

 provements of the method have been published by Born (Bohm u. Oppel) 

 1904, and by Dr. F. P. Mall and his assistants. See contributions to the 

 Science of Medicine, pp. 926-1045. Proceedings of the Atner. Assoc Anatom- 

 ists, 1901, 14th session (1900) p. 193. A. G. Pohlman, Zeit. wiss Mikroskopie, 

 Bd. xxiii, 1906, p. 41. 



To overcome the difficulty of cutting outthe wax plates, Dr. E. L. Mark 

 of Harvard University uses an electrically heated wire moved rapidly by a 

 modified sewing machine (Amer. Acad. Arts and Sciences, March, 1907 ; 

 Science, vol. xxv, 1907 ; Anat. Record April, 1907. 



MODELS OF BLOTTING PAPER 



§ 491. Comparison of Wax and Paper Models. — Wax has 

 certain inherent defects for models : It is expensive, heavy and 

 fragile. It is easily deformed by the temperature of summer, and 

 the amount of time necessary for the preparation of the plates is 

 great. A wax-plate machine is expensive and bulky. 



It therefore seemed worth while to see if there was not some 

 other material obtainable in the open market which would be more 

 suitable and more generally available. , 



Blotting paper seemed promising, and an actual trial showed it 

 to be admirably adapted for the purpose. Since making the first 

 model in 1905 it has been constantly used in the laboratory of 

 embryology in Cornell University. Models made from it were 

 demonstrated before the Association of American' Anatomists in 

 1905 and before the International Congress of Zoology in 1907. 



" The advantages of blotting paper models are the ease and 

 cleanliness of their production and the lightness and durability of 

 the product. The models are broken with difficulty, are easily 

 packed or transported, and when they cleave apart are easily 

 repaired, thus contrasting with the weight and fragility of wax 

 models and their deformation by heat. " 



' ' By this process are secured for the original model recon- 

 structed from microscopic sections, the same qualities which have 



