Desiccation of Albumin ttpon its Coagulability. 331 



to 63° C."* Filtering off the clot and testing the filtrate at higher 

 temperatures yielded no further coagulation. 



If a sample of this (dry) albumin be placed in a flask, the mouth of 

 which is furnished with a cork and attached to a set of drying tubes, 

 and the temperature of the flask raised to 80° C, a short exposure, of 

 at any rate two to three hours, is enough to completely alter the 

 albumin. The object of the drying tubes is to prevent any more 

 moisture than is already present in its substance reaching the albumin 

 from the steam or from any other source. Thus heated, the albumin 

 is found to have become insoluble in water, and in fact to have under- 

 gone a change corresponding to coagulation. 



If, however, the albumin be carefully dried before being subjected to 

 these conditions, the results are quite different. For the present pur- 

 pose it was found to be sufficient to expose a thin layer of albumin in 

 a glass dish to a temperature of 52 — 55° C. in an incubator. This 

 •ensures a very thorough desiccation. The process may be hastened 

 by introducing a vessel of sulphuric acid, though this precaution was 

 not found to be necessary. Thus dried, the albumin loses its shellac 

 or glue-like appearance, and easily crumbles to very small particles. 



On comparing the solubility and coagulability of this specially dried 

 material with the ordinary sample, no difference could be detected in 

 any respect. 



Numerous experiments were made with this dried material, of which 

 the following may be taken as typical. It may be added that the 

 results throughout were almost surprisingly uniform in the different 

 experiments made. 



A sample of the specially dried albumin was introduced in a flask so 

 as to form a thin layer over the bottom. The flask was connected 

 with drying tubes filled with calcium chloride, and with phosphorus 

 pentoxide. The flask was warmed and cooled rapidly several times, 

 in order to cause the contained air to circulate through the drying 

 tubes. 



The temperature of the flask was then raised in a brine bath to 

 102° C, and kept at this temperature during the whole of one day 

 (six hours). Next day, and without opening or disturbing the appa- 

 ratus, the temperature was again raised to 107° C, and finally to 

 110° C. It was maintained between these limits for seven hours ; thus 

 the contents of the flask had been for thirteen hours exposed to a tem- 

 perature of considerably over 100° C. 



On testing the albumin it was found to be soluble in water, and in 

 no way, as far as could be observed, did it differ from the unheated 

 material. On gradually warming the solution side by side with a 



* It is of course known that several factors affect tlie coagulation point. The 

 figures given represent those obtained in my experiments, which were all kept as 

 uniform as possible so as to eliminate the factor of variability. 



