_B._ _Insoluble in boiling water, and yielding by decomposition much leucin and some tyrosin, together with glycocoll and lysatin. Slowly hydrated by boiling dilute acids and by treatment with pepsin-hydrochloric acid._--Elastin. _C._ _Insoluble in water, dilute acids and alkalies, also in gastric and pancreatic juice. Yield leucin and tyrosin by decomposition._--Keratin, neurokeratin. We may now advantageously consider the composition of a few of the more prominent representatives of the individual groups, taking for illustration those bodies which have been most thoroughly studied, and which we may have occasion to refer to in our discussion of proteolysis. I have not included in the table any of the alteration-products of the proteids formed by the action of pepsin-acid, trypsin, or boiling dilute acids, confining myself here simply to those bodies which occur ready-formed in nature. COMPOSITION OF SOME OF THE MORE PROMINENT PROTEIDS OCCURRING IN NATURE.[A] =============================================================================== Substance. | C | H | N | S | O | P | Ash.| Origin. | Author. ------------+-----+----+-----+----+-----+----+-----+-----------+--------------- Serum- |53.05|6.85|16.04|1.77|22.29| |{0.57|Serum from |Hammarsten.[54] albumin | | | | | | |{-- |horse blood| Serum- |52.25|6.65|15.88|2.27|22.95| |{1.84|Pleural |Hammarsten.[54] albumin | | | | | | | |exudation | Egg-albumin |52.25|6.90|15.25|1.93|23.67| | |Non- |Hammarsten.[54] | | | | | | | |coagulated | Egg-albumin |52.33|6.98|15.89|1.83|22.97| | 1.11|Non- |Chittenden and | | | | | | | |coagulated |Bolton.[55] Lacto- |52.19|7.18|15.77|1.73|23.13| | |Cow’s milk |Sebelien.[56] albumin | | | | | | | | | Vegetable- |52.25|6.76|16.07|1.48|23.44| | 0.70|Corn |Chittenden and albumin | | | | | | | |or maize |Osborne.[57] Vegetable- |53.02|6.84|16.80|1.28|22.06| | 0.82|Wheat |Osborne and albumin | | | | | | | | |Voorhees.[58] Proteose, |52.13|6.83|16.55|1.09|23.40| | 0.79|Hemialbu- |Kühne and animal | | | | | | | |mose, urine|Chittenden.[59] Proteose, |50.60|6.68|16.33|1.62|24.77| | 2.99|Corn |Chittenden and vegetable | | | | | | | |or maize |Osborne.[57] Proteose, |51.86|6.82|17.32| | | | 0.25|Wheat |Osborne and vegetable | | | | | | | | |Voorhees.[58] Proteose, |49.98|6.95|18.78| | | | 1.80|Flax-seed |Osborne.[60] vegetable | | | | | | | | | Proteose, |46.52|6.40|18.25| | | | 2.20|Cocoanut |Chittenden and