30 R. G. HOSKINS 



believing thsft even putrefactive products have in the past figured as 

 specific hormones. 



The fact that some at least of the hormones will withstand boiling 

 without serious loss of potency affords a means of eliminating the dis- 

 turbing factors that reside in the protein content of gland extracts. If 

 boiled in weakly acid medium the solution is both sterilized and freed from 

 protein. If the filtrate from such a boiled extract is hermetically sealed 

 or evaporated to dryness it may retain its potency for long periods. 



Investigators in the past have felt free to use such reagents as strong 

 acid or alkali in preparation of extracts in which they hoped to demon- 

 strate hormone constituents. In drawing conclusions from the use of 

 such gland materials, particular caution is necessary.' The body has at 

 its disposal as a menstruum only the tissue fluids which differ relatively 

 little from simple isotonic saline solutions. Accordingly, any "hormone" 

 that requires for its "liberation" such substances as sulphuric acid or 

 potassium hydrate is probably nonexistent in the normal gland. It is 

 true that through the presence of specific enzymes the body is able to 

 form, even in a simple menstruum, elaborate products; but there is no 

 convincing evidence that such enzyme factors are involved in hormone 

 production. More than one elaborate report in the literature if judged by 

 the criterion just discussed would be without significance. 



Many, if not all, unboiled tissue extracts contain substances that are 

 likely to induce intravenous coagulation. Kephalin is particularly im- 

 portant in this regard (Howell). If massive clotting should occur death 

 would at once ensue and the only possible erroneous conclusion that 

 might be drawn would be that the substance was "toxic." Localized clots, 

 however, may be carried to or formed in the nervous system or elsewhere 

 and produce striking effects that upon superficial consideration might seem 

 to bo the result of specific hormones. The inconstancy of such results are 

 sufficient to rule out specificity. 



One striking fact noted in connection with experiments on the pharma- 

 codynamics of gland extracts is that a given apparently specific reaction 

 can be obtained from extracts of several different glands. For example, 

 augmented flow of milk from the lactating mammary glands has' been 

 reported following the administration of extracts of the posterior lobe of 

 the hypophysis, the corpus lutenm, the uterus, the lactating mammary 

 glands, the thymus, and the pineal. Likewise, contractions of the bladder 

 have been reported following injections of extracts of the thymus, the thy- 

 roid, the testicles, the prostate, and the pancreas. Following the reason- 

 ing which has been employed in many reports of endocrin researches, 

 each of the glands mentioned may be regarded as normally controlling 

 the activity of the mammae or the bladder. Such multiple control is, 

 to say the least, highly improbable. 



Another experimental difficulty encountered in experiments with 



